javascript inline conditional assignment

Mastering the JavaScript Inline If: Ternary Operator Like a Pro

Hey there, fellow coders! Today, we’re diving into the nitty-gritty of JavaScript’s inline if, also known as the ternary operator. This little gem is like a Swiss Army knife for your code, offering a sleek and efficient way to handle conditional logic.

What’s the Deal with the Ternary Operator?

In JavaScript, the ternary operator is a one-liner that can replace a traditional if-else statement. It’s a true code condenser. The syntax is pretty straightforward:

It reads as: “Is the condition true? Then do this. If not, do that.” Let’s see it in action:

React: Inline If with Ternary Operator

When you’re working with React, the ternary operator becomes your go-to for conditional rendering. No need to bloat your JSX with clunky if statements!

This keeps your components clean and your logic crystal clear. Plus, it’s inline with JSX, so you can keep the flow without breaking into curly braces and return statements.

Vue.js: The Elegance of v-if and Ternary Operators

Vue.js offers its own directive for conditionals, v-if , but sometimes you want that inline simplicity. Ternary operators in Vue templates work just like in vanilla JS:

Keep in mind that Vue’s reactivity system will make sure the UI updates when user.isAuthenticated changes. It’s like magic, but you know, the JavaScript kind.

Angular: ngIf vs. Ternary Operator

Angular has ngIf , but there are times when a ternary operator is more convenient, especially when you’re dealing with simple expressions within your templates:

This is Angular’s template syntax, so it’s baked into your HTML like a delicious piece of logic lasagna. Yum!

Svelte: Reactive Statements and the Ternary Operator

Svelte is all about reactivity and minimalism, and the ternary operator fits right in. Use it within curly braces in your HTML template, and Svelte takes care of the rest:

Svelte’s reactivity system is tightly integrated, so changes to isMember will automatically update the text displayed. It’s like Svelte and the ternary operator were made for each other.

Embracing the Ternary Operator in Your Workflow

The ternary operator is a powerful tool that can simplify your code across different JavaScript frameworks. It’s about writing less and doing more, and who doesn’t love that? Whether you’re a React fanboy, a Vue virtuoso, an Angular aficionado, or a Svelte savant, the ternary operator can make your code cleaner and more readable.

Stay tuned for the second half of this article where we’ll dive even deeper into the ternary operator, exploring edge cases, best practices, and advanced scenarios. You’ll be a ternary operator wizard by the end of it, I promise!

Alright, we’ve covered the basics of the ternary operator in various JavaScript frameworks. Now, let’s level up and explore some advanced uses and best practices to ensure your code remains as clean and efficient as possible.

Chaining Ternary Operators

Yes, you can chain ternary operators for multiple conditions, but tread carefully – it can get confusing quickly! Here’s how you might do it:

While this works, it’s not the most readable. If your conditions are complex, consider using if...else statements or a switch for clarity.

Nested Ternary Operators

Nesting ternary operators is like chaining, but with conditions within conditions. Again, this can be hard to read, so use it sparingly:

For the love of readability, don’t go overboard with nesting. Your future self and fellow developers will thank you.

Best Practices for Ternary Operators

Here are some quick tips to keep your ternary operator usage sharp and sensible:

Keep It Simple : If your ternary logic is getting complex, break it down or choose a different conditional approach.
Formatting Matters : Proper indentation and line breaks can make a world of difference for readability.
Comment Wisely : A well-placed comment can clarify intent without cluttering code.
Consistency Is Key : Stick to a consistent style in how you use ternary operators across your codebase.

Ternary Operators and Accessibility

When working with UI elements, especially in frameworks like React, remember that accessibility matters. Ternary operators can control the rendering of elements, but ensure that you’re not compromising accessibility:

By using aria-hidden , we maintain accessibility by informing assistive technologies about the state of the menu.

Performance Considerations

Ternary operators are generally fast, but be mindful of performance, especially when using them in large-scale applications or within loops. The performance impact is usually negligible, but it’s good practice to keep an eye on it during code reviews and profiling.

Debugging Ternary Operators

Debugging ternary operators can be tricky since you can’t set a breakpoint on individual parts of the operator like you can with an if...else statement. If you’re having trouble, consider temporarily converting the ternary into a more verbose conditional to debug it more easily.

Conclusion: The Ternary Operator Is Your Friend (With Benefits)

The ternary operator is a fantastic tool in your JavaScript toolkit. It’s concise, versatile, and when used properly, can make your code cleaner and easier to maintain. Just remember to use it judiciously and always keep readability in mind.

Whether you’re working with React, Vue, Angular, or Svelte, the ternary operator can help you write more declarative and elegant code. Embrace it, but don’t abuse it, and you’ll be well on your way to becoming a more effective and efficient developer.

And there you have it, folks – a comprehensive dive into JavaScript’s inline if, the ternary operator. Use it well, and may your code be as smooth and efficient as the operator itself!

Quick Tip: How to Use the Ternary Operator in JavaScript

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Using the Ternary Operator for Value Assignment

Using the ternary operator for executing expressions, using the ternary operator for null checks, nested conditions, codepen example, faqs on how to use the ternary operator in javascript.

In this tutorial, we’ll explore the syntax of the ternary operator in JavaScript and some of its common uses.

The ternary operator (also known as the conditional operator ) can be used to perform inline condition checking instead of using if...else statements. It makes the code shorter and more readable. It can be used to assign a value to a variable based on a condition, or execute an expression based on a condition.

The ternary operator accepts three operands; it’s the only operator in JavaScript to do that. You supply a condition to test, followed by a questions mark, followed by two expressions separated by a colon. If the condition is considered to be true ( truthy ), the first expression is executed; if it’s considered to be false, the final expression is executed.

It’s used in the following format:

Here, condition is the condition to test. If its value is considered to be true , expr1 is executed. Otherwise, if its value is considered to be false , expr2 is executed.

expr1 and expr2 are any kind of expression. They can be variables, function calls, or even other conditions.

For example:

One of the most common use cases of ternary operators is to decide which value to assign to a variable. Often, a variable’s value might depend on the value of another variable or condition.

Although this can be done using the if...else statement, it can make the code longer and less readable. For example:

In this code example, you first define the variable message . Then, you use the if...else statement to determine the value of the variable.

This can be simply done in one line using the ternary operator:

Ternary operators can be used to execute any kind of expression.

For example, if you want to decide which function to run based on the value of a variable, you can do it like this using the if...else statement:

This can be done in one line using the ternary operator:

If feedback has the value yes , then the sayThankYou function will be called and executed. Otherwise, the saySorry function will be called and executed.

In many cases, you might be handling variables that may or may not have a defined value — for example, when retrieving results from user input, or when retrieving data from a server.

Using the ternary operator, you can check that a variable is not null or undefined just by passing the variable name in the position of the condition operand.

This is especially useful when the variable is an object . If you try to access a property on an object that’s actually null or undefined , an error will occur. Checking that the object is actually set first can help you avoid errors.

In the first part of this code block, book is an object with two properties — name and author . When the ternary operator is used on book , it checks that it’s not null or undefined . If it’s not — meaning it has a value — the name property is accessed and logged into the console. Otherwise, if it’s null, No book is logged into the console instead.

Since book is not null , the name of the book is logged in the console. However, in the second part, when the same condition is applied, the condition in the ternary operator will fail, since book is null . So, “No book” will be logged in the console.

Although ternary operators are used inline, multiple conditions can be used as part of a ternary operator’s expressions. You can nest or chain more than one condition to perform condition checks similar to if...else if...else statements.

For example, a variable’s value may depend on more than one condition. It can be implemented using if...else if...else :

In this code block, you test multiple conditions on the score variable to determine the letter grading of the variable.

These same conditions can be performed using ternary operators as follows:

The first condition is evaluated, which is score < 50 . If it’s true , then the value of grade is F . If it’s false , then the second expression is evaluated which is score < 70 .

This keeps going until either all conditions are false , which means the grade’s value will be A , or until one of the conditions is evaluated to be true and its truthy value is assigned to grade .

In this live example, you can test how the ternary operator works with more multiple conditions.

If you enter a value less than 100, the message “Too Low” will be shown. If you enter a value greater than 100, the message “Too High” will be shown. If you enter 100, the message “Perfect” will be shown.

See the Pen Ternary Operator in JS by SitePoint ( @SitePoint ) on CodePen .

As explained in the examples in this tutorial, the ternary operator in JavaScript has many use cases. In many situations, the ternary operator can increase the readability of our code by replacing lengthy if...else statements.

What is the Syntax of the Ternary Operator in JavaScript?

The ternary operator in JavaScript is a shorthand way of writing an if-else statement. It is called the ternary operator because it takes three operands: a condition, a result for true, and a result for false. The syntax is as follows: condition ? value_if_true : value_if_false In this syntax, the condition is an expression that evaluates to either true or false. If the condition is true, the operator returns the value_if_true . If the condition is false, it returns the value_if_false .

Can I Use Multiple Ternary Operators in a Single Statement?

Yes, you can use multiple ternary operators in a single statement. This is known as “nesting”. However, it’s important to note that using too many nested ternary operators can make your code harder to read and understand. Here’s an example of how you can nest ternary operators: let age = 15; let beverage = (age >= 21) ? "Beer" : (age < 18) ? "Juice" : "Cola"; console.log(beverage); // Output: "Juice"

Can Ternary Operators Return Functions in JavaScript?

Yes, the ternary operator can return functions in JavaScript. This can be useful when you want to execute different functions based on a condition. Here’s an example: let greeting = (time < 10) ? function() { alert("Good morning"); } : function() { alert("Good day"); }; greeting();

How Does the Ternary Operator Compare to If-Else Statements in Terms of Performance?

In terms of performance, the difference between the ternary operator and if-else statements is negligible in most cases. Both are used for conditional rendering, but the ternary operator can make your code more concise.

Can Ternary Operators be Used Without Else in JavaScript?

No, the ternary operator in JavaScript requires both a true and a false branch. If you don’t need to specify an action for the false condition, consider using an if statement instead.

How Can I Use the Ternary Operator with Arrays in JavaScript?

You can use the ternary operator with arrays in JavaScript to perform different actions based on the condition. Here’s an example: let arr = [1, 2, 3, 4, 5]; let result = arr.length > 0 ? arr[0] : 'Array is empty'; console.log(result); // Output: 1

Can Ternary Operators be Used for Multiple Conditions?

Yes, you can use ternary operators for multiple conditions. However, it can make your code harder to read if overused. Here’s an example: let age = 20; let type = (age < 13) ? "child" : (age < 20) ? "teenager" : "adult"; console.log(type); // Output: "teenager"

Can Ternary Operators be Used in Return Statements?

Yes, you can use ternary operators in return statements. This can make your code more concise. Here’s an example: function isAdult(age) { return (age >= 18) ? true : false; } console.log(isAdult(20)); // Output: true

Can Ternary Operators be Used with Strings in JavaScript?

Yes, you can use ternary operators with strings in JavaScript. Here’s an example: let name = "John"; let greeting = (name == "John") ? "Hello, John!" : "Hello, Stranger!"; console.log(greeting); // Output: "Hello, John!"

Can Ternary Operators be Used with Objects in JavaScript?

Yes, you can use ternary operators with objects in JavaScript. Here’s an example: let user = { name: "John", age: 20 }; let greeting = (user.age >= 18) ? "Hello, Adult!" : "Hello, Kid!"; console.log(greeting); // Output: "Hello, Adult!"

Dianne is SitePoint's newsletter editor. She especiallly loves learning about JavaScript, CSS and frontend technologies.

Mastering JavaScript Inline If Statements: A Complete 2021 Guide

Conditional logic allows us to control program flow based on dynamic values and user input. It is one of the core building blocks of writing reusable, maintainable code.

If you‘ve written any substantial JavaScript, you‘ve surely used standard if/else statements many times. But did you know there are other more compact ways to write conditionals right inside expressions?

Inline if statements provide a minimized syntax for conditionally executing code or evaluating different expressions. In this comprehensive guide, you‘ll learn:

What are inline if statements and when should you use them?
How to write inline if/else logic using ternary operators
When to use logical && instead for conditionals
Pros, cons, and best practices for inline if usage
How performance compares to standard if statements
Examples and real-world applications for writing better conditional code

By the end, you‘ll master these core techniques to write cleaner conditional logic in your JavaScript code. Let‘s get started!

Why Use Inline If Statements?

Before we look at the syntax, when might you want to use an inline if statement vs a standard multiline if block?

Some common use cases for inline if:

Assigning variables or passing function arguments conditionally
Returning different values from a function based on a condition
Selecting between two expressions based on a boolean test
Conditionally executing a statement or block of code

Benefits of inline if include:

More compact "one line" syntax
Avoid unnecessary code nesting and blocks
Improved readability in some cases
Easier to return or assign conditional values directly

However, for more complex conditional logic, standard if statements are usually preferable.

As a rule of thumb, consider using inline if for simpleconditionals, and standard if statements for longer multiline logic.

Now let‘s look at the different options for writing inline if/else in JavaScript…

Inline If with the Ternary Operator

The ternary operator provides us with the most flexibility and options for inline conditional logic.

Ternary Syntax

Here is the syntax for a ternary operator:

It checks the condition , and executes either the exprIfTrue or exprIfFalse based on the result.

Some examples:

The condition can be any valid JavaScript expression that evaluates to true/truthy or false/falsy.

This allows us to assign values or return results inline based on a conditional check.

Ternary for Multiple Conditions

We can also chain multiple ternary operators together to have multiple case conditions:

Here we have nested ternaries to check for different age brackets.

Chaining ternaries works well for a limited number of conditions. Beyond 2-3, it often hurts readability – so consider standard if/else instead for more complex logic flows.

Ternary Use Cases

Some common examples of using ternary operators:

Assign variable values conditionally
Conditionally pass function arguments
Return different function results based on condition
Choose between two expressions

Ternary vs If…Else

So when should you prefer the ternary operator vs standard if/else conditional statements?

Consider ternary when:

You need to assign a variable or return value conditionally
The logic is simple (1-2 conditions)
You want a compact "one liner" syntax
Readability is improved by avoiding nesting/blocks

Prefer standard if statement when:

Multiple complex conditions and logic branches
Multiline logic that is harder to read in ternary
Code clarity is improved by blocks and indentation
Nesting ternaries hurts readability

The ternary operator is ideal for quick inline conditional checks and assignments. For longer conditional flows, standard if statements are often preferable.

Inline If using Logical &&

Along with the ternary operator, we can also use JavaScript‘s logical AND (&&) for inline conditionals.

Here is an example:

The && works by first evaluating the left side. If it is truthy, it also executes the right side. If falsy, it stops without running the right side.

Some other examples:

When to use Logical &&

The && operator is best for:

Conditionally executing a function or expression
Defaulting variables if null/undefined
Short circuiting execution if falsy

It provides a minimal syntax for these cases.

However, the && operator does have limitations:

Only runs right side, no ability to return else value
Can‘t use it to return different values like ternary
Only useful for conditionally executing code, not returning

So in summary, && is a lighter inline syntax that works well for conditionally executing code. The ternary operator is more flexible overall.

Comparing Ternary and && Performance

An important consideration is if these inline conditionals have any performance differences compared to standard if statements.

Good news – JavaScript engines are excellent at optimizing conditionals.

According to benchmarks, there is negligible difference in performance between ternary, &&, and regular if statements.

Some notable findings from performance tests:

All 3 options optimize to similar assembly output
AND is fractionally faster in isolated tests
Performance varies more based on code structure
Don‘t optimize prematurely based on assumptions

So you can focus on writing clean readable code rather than micro-performance. Only optimize conditionals when you have evidence of real bottlenecks.

Common Mistakes to Avoid

Let‘s now go over some best practices and common mistakes when using inline if statements:

Avoid long or complex ternary expressions – these hurt readability. Standard if statements are better suited.
Don‘t nest ternaries too deeply – Chaining beyond 2-3 levels often makes code harder to understand.
Always wrap conditions in () – This avoids incorrect operator precedence.
Use good variable names – Well-named variables help document inline conditionals.
Watch out for assignment vs equality – Using = rather than == can lead to unintended results.
Be careful when returning object literals – The { } syntax affects statement interpretation.

Following these best practices will help you avoid issues when leveraging inline if/else conditionals.

Putting Into Practice

The best way to get comfortable with inline conditionals is seeing examples of how they can be used in real code.

Here are some practical applications:

There are many cases where compact inline if/else logic can help write cleaner code vs standard if blocks.

Key Takeaways

Here are some key tips to remember:

Use ternary operators for conditional assignment/returns
Logical && has a lighter syntax for conditionally executing code
Standard if statements are better for complex multiline logic
Neither ternary nor && have significant performance costs
Balance readability vs brevity when choosing expressions
Avoid nesting ternaries too deeply

With the right approach, inline if statements allow you to write conditional code that is clear, compact, and efficient.

JavaScript offers flexible options for inline conditionals – from ternary and && operators to regular multiline if. By mastering all these techniques, you can write professional-grade conditional logic.

I hope this guide has helped demystify inline if statements! Let me know if you have any other questions.

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Inline if Statement in JavaScript
JavaScript Howtos

Simple Inline if Statement With Ternary Operation in JavaScript

Multiple condition inline if statement ternary operation in javascript, inline if statement with logical operator in javascript.

Conditional operation is one of the basic coding conceptions for any programming language. The convention is to infer the best fit output from multiple available conditions. JavaScript supports both the usual if...else structure and the ternary operators.

In the following section, we will introduce how to apply conditional statements using ternary operators and logical operators.

Generally, this kind of coding practice states the base condition first and separates the possible outcome by a ? . The possible results are set apart with a colon (:) . Ternary operation structure only takes a single line of code to bring the result, thus named as inline if statement.

Code Snippet:

The example explains the condition where the variable x is compared with the variable y . If x is greater than y , then z holds the value of x , other than that value of y . This is the alternative to the basic if...else structure.

Multiple conditions refer to more than one condition; more specifically, it is the structure for if...else if...else . Each condition scope will have a return case, and the applicable condition’s return value is the answer. The documentation gives a better preview for the case.

According to the output, it is seen that here an if statement (x>y) was present also upon that there was a return case "true" . Later for if else , we have (x<y) as the condition, and that returns "false" . Also, if the applied condition gets matched, we return "false" , which is our else statement.

In this practice, a given condition that satisfies the return value is written after the (&&) operator. And if it is directed to the else condition, the return value is set after the || operator. Let’s see the demonstration with a code example.

Era is an observer who loves cracking the ambiguos barriers. An AI enthusiast to help others with the drive and develop a stronger community.

How to Use the Ternary Operator in JavaScript – JS Conditional Example

The ternary operator is a helpful feature in JavaScript that allows you to write concise and readable expressions that perform conditional operations on only one line.

In this article, you will learn why you may want to use the ternary operator, and you will see an example of how to use it. You will also learn some of the best practices to keep in mind when you do use it.

Let's get into it!

What Is The Ternary Operator in JavaScript?

The ternary operator ( ?: ), also known as the conditional operator, is a shorthand way of writing conditional statements in JavaScript – you can use a ternary operator instead of an if..else statement.

A ternary operator evaluates a given condition, also known as a Boolean expression, and returns a result that depends on whether that condition evaluates to true or false .

Why Use the Ternary Operator in JavaScript?

You may want to use the ternary operator for a few reasons:

Your code will be more concise : The ternary operator has minimal syntax. You will write short conditional statements and fewer lines of code, which makes your code easier to read and understand.
Your code will be more readable : When writing simple conditions, the ternary operator makes your code easier to understand in comparison to an if..else statement.
Your code will be more organized : The ternary operator will make your code more organized and easier to maintain. This comes in handy when writing multiple conditional statements. The ternary operator will reduce the amount of nesting that occurs when using if..else statements.
It provides flexibility : The ternary operator has many use cases, some of which include: assigning a value to a variable, rendering dynamic content on a web page, handling function arguments, validating data and handling errors, and creating complex expressions.
It enhances performance : In some cases, the ternary operator can perform better than an if..else statement because the ternary operator gets evaluated in a single step.
It always returns a value : The ternary operator always has to return something.

How to Use the Ternary Operator in JavaScript – a Syntax Overview

The operator is called "ternary" because it is composed of three parts: one condition and two expressions.

The general syntax for the ternary operator looks something similar to the following:

Let's break it down:

condition is the Boolean expression you want to evaluate and determine whether it is true or false . The condition is followed by a question mark, ? .
ifTrueExpression is executed if the condition evaluates to true .
ifFalseExpression is executed if the condition evaluates to false .
The two expressions are separated by a colon, . .

The ternary operator always returns a value that you assign to a variable:

Next, let's look at an example of how the ternary operator works.

How to Use the Ternary Operator in JavaScript

Say that you want to check whether a user is an adult:

In this example, I used the ternary operator to determine whether a user's age is greater than or equal to 18 .

Firstly, I used the prompt() built-in JavaScript function.

This function opens a dialog box with the message What is your age? and the user can enter a value.

I store the user's input in the age variable.

Next, the condition ( age >= 18 ) gets evaluated.

If the condition is true , the first expression, You are an adult , gets executed.

Say the user enters the value 18 .

The condition age >= 18 evaluates to true :

If the condition is false , the second expression, You are not an adult yet , gets executed.

Say the user enters the value 17 .

The condition age >= 18 now evaluates to false :

As mentioned earlier, you can use the ternary operator instead of an if..else statement.

Here is how you would write the same code used in the example above using an if..else statement:

Ternary Operator Best Practices in JavaScript

Something to keep in mind when using the ternary operator is to keep it simple and don't overcomplicate it.

The main goal is for your code to be readable and easily understandable for the rest of the developers on your team.

So, consider using the ternary operator for simple statements and as a concise alternative to if..else statements that can be written in one line.

If you do too much, it can quickly become unreadable.

For example, in some cases, using nested ternary operators can make your code hard to read:

If you find yourself nesting too many ternary operators, consider using if...else statements instead.

Wrapping Up

Overall, the ternary operator is a useful feature in JavaScript as it helps make your code more readable and concise.

Use it when a conditional statement can be written on only one line and keep code readability in mind.

Thanks for reading, and happy coding! :)

Write an Inline IF Statement in JavaScript (with code)

Conditional statements are a fundamental aspect of programming, as they allow developers to add logic and control the basic flow of a program based on specific conditions. In this article, we will learn different ways of creating inline If statements in JavaScript, such as using ternary operators and logical operators.

What are Inline IF Statements in JavaScript?

As we know IF statements are used for checking a specific condition. It often consists of an else block, when the “if” condition is false then the “else” block is executed.

A simple syntax of “if-else” is given below:

We want to learn about “inline if”, which means compiling this whole code into a single line. Let’s learn how to do this:

1) Using Ternary Operators

The best way to write an inline IF statement in Javascript is by using Ternary Operator. The ternary operator is denoted by a question mark(?) and a colon(:), allowing for concise conditional logic and action.

The syntax is as follows:

Here, Condition is a statement which can either be true or false, returning trueAns or falseAns respectively.

Therefore we can see that if the condition is true then the statement after ? executes and in other cases, statement after : executes.

2) Using Logical Operators

Another method for the same is using a combination of AND(&&) and OR(||) operators and executing the if else condition in a single line.

As we know while executing a logical AND both the operands need to be true to return true and for an OR, we will return true even if one of the operands is true. The logical OR operator returns the first true operand, or the last operand if none are true.

Here is an example for more understanding:

Here’s how it works:

First of all, we will encounter `a>b`, which will return false as 10 is smaller than 12.
Then `a>b && a` will return false as for AND(&&) both the operands need to be true for returning true, and here a>b is false.
After that `a>b && a || b` is a combination of both AND and OR operators. The expression is evaluated from left to right.
Since `a>b && a` is false, the expression becomes false || b.
And we know that the logical OR operator returns the first true operand, or the last operand if none are true.
Here it returns b because the second operand is true.

3) Multiple Conditions Using Ternary Operator

If we have nested or multiple if-else blocks, we can still use a ternary operator to write this whole code in a single line of code. Its syntax is as follows:

Here if first “condition1” is true then trueAns1 part will be executed, else if “condition2” is true then it will result in the execution of trueAns2 and falseAns is the else part.

Let’s see this one line of code by breaking it into pieces:

Here we can see how if-else if-else is executed in a single line of code. If a is greater than b, it returns the value of a. If a is less than b, it returns the value of b. And if none of the conditions are met, it returns “NaN”.

Should I use inline if in JavaScript?

The usage of inline if statements depends on the readability of your code. Using such statements can make your code more concise, but remember that it is also harder to read, and debug. Also, if your condition is quite complex, it is recommended to use the traditional if-else statement for clarity. Also, if you are working in a company, most enterprises don’t recommend using such IF statements.

We explored different techniques for implementing inline If statements in JavaScript. So, the next time you come across a situation where you need to use if else statements in your code, consider replacing your code with inline if statements for a more concise and readable code. Need some more explanation? Get JavaScript Assignment help from experts online.

Nikita Arora

I'm Nikita, a B.Tech Computer Engineering student. My passion lies in web development, data structures, and algorithms. Committed to continuous learning, I find immense joy in sharing insights and fostering collaboration among like-minded peers in web development. Excited about exploring interesting opportunities in technology.

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Making decisions in your code — conditionals

Overview: JavaScript building blocks

In any programming language, the code needs to make decisions and carry out actions accordingly depending on different inputs. For example, in a game, if the player's number of lives is 0, then it's game over. In a weather app, if it is being looked at in the morning, show a sunrise graphic; show stars and a moon if it is nighttime. In this article, we'll explore how so-called conditional statements work in JavaScript.

Prerequisites:	A basic understanding of HTML, CSS, and .
Objective:	To understand how to use conditional structures in JavaScript.

You can have it on one condition!

Human beings (and other animals) make decisions all the time that affect their lives, from small ("should I eat one cookie or two?") to large ("should I stay in my home country and work on my father's farm, or should I move to America and study astrophysics?")

Conditional statements allow us to represent such decision making in JavaScript, from the choice that must be made (for example, "one cookie or two"), to the resulting outcome of those choices (perhaps the outcome of "ate one cookie" might be "still felt hungry", and the outcome of "ate two cookies" might be "felt full, but mom scolded me for eating all the cookies".)

A cartoon character resembling a person holding a cookie jar labeled 'Cookies'. There is a question mark above the head of the character. There are two speech bubbles. The left speech bubble has one cookie. The right speech bubble has two cookies. Together it implies the character is trying to decide if it wants to one cookie or two cookies.

if...else statements

Let's look at by far the most common type of conditional statement you'll use in JavaScript — the humble if...else statement .

Basic if...else syntax

Basic if...else syntax looks like this:

Here we've got:

The keyword if followed by some parentheses.
A condition to test, placed inside the parentheses (typically "is this value bigger than this other value?", or "does this value exist?"). The condition makes use of the comparison operators we discussed in the last module and returns true or false .
A set of curly braces, inside which we have some code — this can be any code we like, and it only runs if the condition returns true .
The keyword else .
Another set of curly braces, inside which we have some more code — this can be any code we like, and it only runs if the condition is not true — or in other words, the condition is false .

This code is pretty human-readable — it is saying " if the condition returns true , run code A, else run code B"

You should note that you don't have to include the else and the second curly brace block — the following is also perfectly legal code:

However, you need to be careful here — in this case, the second block of code is not controlled by the conditional statement, so it always runs, regardless of whether the condition returns true or false . This is not necessarily a bad thing, but it might not be what you want — often you want to run one block of code or the other, not both.

As a final point, while not recommended, you may sometimes see if...else statements written without the curly braces:

This syntax is perfectly valid, but it is much easier to understand the code if you use the curly braces to delimit the blocks of code, and use multiple lines and indentation.

A real example

To understand this syntax better, let's consider a real example. Imagine a child being asked for help with a chore by their mother or father. The parent might say "Hey sweetheart! If you help me by going and doing the shopping, I'll give you some extra allowance so you can afford that toy you wanted." In JavaScript, we could represent this like so:

This code as shown always results in the shoppingDone variable returning false , meaning disappointment for our poor child. It'd be up to us to provide a mechanism for the parent to set the shoppingDone variable to true if the child did the shopping.

Note: You can see a more complete version of this example on GitHub (also see it running live .)

The last example provided us with two choices, or outcomes — but what if we want more than two?

There is a way to chain on extra choices/outcomes to your if...else — using else if . Each extra choice requires an additional block to put in between if () { } and else { } — check out the following more involved example, which could be part of a simple weather forecast application:

Here we've got an HTML <select> element allowing us to make different weather choices, and a simple paragraph.
In the JavaScript, we are storing a reference to both the <select> and <p> elements, and adding an event listener to the <select> element so that when its value is changed, the setWeather() function is run.
When this function is run, we first set a variable called choice to the current value selected in the <select> element. We then use a conditional statement to show different text inside the paragraph depending on what the value of choice is. Notice how all the conditions are tested in else if () { } blocks, except for the first one, which is tested in an if () { } block.
The very last choice, inside the else { } block, is basically a "last resort" option — the code inside it will be run if none of the conditions are true . In this case, it serves to empty the text out of the paragraph if nothing is selected, for example, if a user decides to re-select the "--Make a choice--" placeholder option shown at the beginning.

Note: You can also find this example on GitHub ( see it running live on there also.)

A note on comparison operators

Comparison operators are used to test the conditions inside our conditional statements. We first looked at comparison operators back in our Basic math in JavaScript — numbers and operators article. Our choices are:

=== and !== — test if one value is identical to, or not identical to, another.
< and > — test if one value is less than or greater than another.
<= and >= — test if one value is less than or equal to, or greater than or equal to, another.

We wanted to make a special mention of testing boolean ( true / false ) values, and a common pattern you'll come across again and again. Any value that is not false , undefined , null , 0 , NaN , or an empty string ( '' ) actually returns true when tested as a conditional statement, therefore you can use a variable name on its own to test whether it is true , or even that it exists (that is, it is not undefined.) So for example:

And, returning to our previous example about the child doing a chore for their parent, you could write it like this:

Nesting if...else

It is perfectly OK to put one if...else statement inside another one — to nest them. For example, we could update our weather forecast application to show a further set of choices depending on what the temperature is:

Even though the code all works together, each if...else statement works completely independently of the other one.

Logical operators: AND, OR and NOT

If you want to test multiple conditions without writing nested if...else statements, logical operators can help you. When used in conditions, the first two do the following:

&& — AND; allows you to chain together two or more expressions so that all of them have to individually evaluate to true for the whole expression to return true .
|| — OR; allows you to chain together two or more expressions so that one or more of them have to individually evaluate to true for the whole expression to return true .

To give you an AND example, the previous example snippet can be rewritten to this:

So for example, the first code block will only be run if choice === 'sunny' and temperature < 86 return true .

Let's look at a quick OR example:

The last type of logical operator, NOT, expressed by the ! operator, can be used to negate an expression. Let's combine it with OR in the above example:

In this snippet, if the OR statement returns true , the NOT operator will negate it so that the overall expression returns false .

You can combine as many logical statements together as you want, in whatever structure. The following example executes the code inside only if both OR statements return true, meaning that the overall AND statement will return true:

A common mistake when using the logical OR operator in conditional statements is to try to state the variable whose value you are checking once, and then give a list of values it could be to return true, separated by || (OR) operators. For example:

In this case, the condition inside if () will always evaluate to true since 7 (or any other non-zero value) always evaluates to true . This condition is actually saying "if x equals 5, or 7 is true — which it always is". This is logically not what we want! To make this work you've got to specify a complete test on either side of each OR operator:

switch statements

if...else statements do the job of enabling conditional code well, but they are not without their downsides. They are mainly good for cases where you've got a couple of choices, and each one requires a reasonable amount of code to be run, and/or the conditions are complex (for example, multiple logical operators). For cases where you just want to set a variable to a certain choice of value or print out a particular statement depending on a condition, the syntax can be a bit cumbersome, especially if you've got a large number of choices.

In such a case, switch statements are your friend — they take a single expression/value as an input, and then look through several choices until they find one that matches that value, executing the corresponding code that goes along with it. Here's some more pseudocode, to give you an idea:

The keyword switch , followed by a set of parentheses.
An expression or value inside the parentheses.
The keyword case , followed by a choice that the expression/value could be, followed by a colon.
Some code to run if the choice matches the expression.
A break statement, followed by a semicolon. If the previous choice matches the expression/value, the browser stops executing the code block here, and moves on to any code that appears below the switch statement.
As many other cases (bullets 3–5) as you like.
The keyword default , followed by exactly the same code pattern as one of the cases (bullets 3–5), except that default does not have a choice after it, and you don't need the break statement as there is nothing to run after this in the block anyway. This is the default option that runs if none of the choices match.

Note: You don't have to include the default section — you can safely omit it if there is no chance that the expression could end up equaling an unknown value. If there is a chance of this, however, you need to include it to handle unknown cases.

A switch example

Let's have a look at a real example — we'll rewrite our weather forecast application to use a switch statement instead:

Note: You can also find this example on GitHub (see it running live on there also.)

Ternary operator

There is one final bit of syntax we want to introduce you to before we get you to play with some examples. The ternary or conditional operator is a small bit of syntax that tests a condition and returns one value/expression if it is true , and another if it is false — this can be useful in some situations, and can take up a lot less code than an if...else block if you have two choices that are chosen between via a true / false condition. The pseudocode looks like this:

So let's look at a simple example:

Here we have a variable called isBirthday — if this is true , we give our guest a happy birthday message; if not, we give her the standard daily greeting.

Ternary operator example

The ternary operator is not just for setting variable values; you can also run functions, or lines of code — anything you like. The following live example shows a simple theme chooser where the styling for the site is applied using a ternary operator.

Here we've got a <select> element to choose a theme (black or white), plus a simple h1 to display a website title. We also have a function called update() , which takes two colors as parameters (inputs). The website's background color is set to the first provided color, and its text color is set to the second provided color.

Finally, we've also got an onchange event listener that serves to run a function containing a ternary operator. It starts with a test condition — select.value === 'black' . If this returns true , we run the update() function with parameters of black and white, meaning that we end up with a background color of black and a text color of white. If it returns false , we run the update() function with parameters of white and black, meaning that the site colors are inverted.

Active learning: A simple calendar

In this example, you are going to help us finish a simple calendar application. In the code you've got:

A <select> element to allow the user to choose between different months.
An onchange event handler to detect when the value selected in the <select> menu is changed.
A function called createCalendar() that draws the calendar and displays the correct month in the h1 element.

We need you to write a conditional statement inside the onchange handler function, just below the // ADD CONDITIONAL HERE comment. It should:

Look at the selected month (stored in the choice variable. This will be the <select> element value after the value changes, so "January" for example.)
Set a variable called days to be equal to the number of days in the selected month. To do this you'll have to look up the number of days in each month of the year. You can ignore leap years for the purposes of this example.
You are advised to use logical OR to group multiple months together into a single condition; many of them share the same number of days.
Think about which number of days is the most common, and use that as a default value.

If you make a mistake, you can always reset the example with the "Reset" button. If you get really stuck, press "Show solution" to see a solution.

Active learning: More color choices

In this example, you are going to take the ternary operator example we saw earlier and convert the ternary operator into a switch statement to allow us to apply more choices to the simple website. Look at the <select> — this time you'll see that it has not two theme options, but five. You need to add a switch statement just underneath the // ADD SWITCH STATEMENT comment:

It should accept the choice variable as its input expression.
For each case, the choice should equal one of the possible <option> values that can be selected, that is, white , black , purple , yellow , or psychedelic . Note that the option values are lowercase, while the option labels , as displayed in the live output, are capitalized. You should use the lowercase values in your code.
For each case, the update() function should be run, and be passed two color values, the first one for the background color, and the second one for the text color. Remember that color values are strings, so they need to be wrapped in quotes.

Test your skills!

You've reached the end of this article, but can you remember the most important information? You can find some further tests to verify that you've retained this information before you move on — see Test your skills: Conditionals .

And that's all you really need to know about conditional structures in JavaScript right now! If there is anything you didn't understand, feel free to read through the article again, or contact us to ask for help.

Comparison operators
Conditional statements in detail
if...else reference
Conditional (ternary) operator reference

How to Use the Ternary Operator in JavaScript

The ternary operator is a concise way of expressing conditional statements in a single line of JavaScript code. Our expert explains how it works.

Conditional statements allow programmers to control the execution of code based on logical conditions. Like many other programming languages, JavaScript features if/else statements that achieve this goal.

What Is The Ternary (Conditional) Operator in JavaScript?

An alternative to the if/else statement, the ternary operator allows JavaScript developers to write concise conditional statements. It is written as “?:” and takes three operands; a logical condition, a value to return if true, and a value to return if false .

But it’s common knowledge among developers that if/else statements with lots of conditions can get messy. They often make scripts unnecessarily long, difficult to debug, and hard to maintain. Fortunately, JavaScript’s ternary operator provides an alternative to the if/else statement, allowing for more concise and maintainable code.

In this article, we’ll write conditional statements with the ternary operator and learn to use it in different situations.

More From Rory Spanton Polynomial Regression: An Introduction

Writing a Simple Expression With the Ternary Operator

The ternary operator gets its name by being the only operator in JavaScript that takes three operands, or parts. The first part of a ternary operation is a logical condition that returns a true or false value. Then, after a question mark , come two expressions, separated by a colon. The first is an expression to execute if the logical condition is true, while the second expression executes if the condition is false. The generic form of the function is below.

The ternary expression is an alternative to the conventional if/else statement. The if/else statement below is equivalent to the ternary operation above.

Because of its similarities to the if/else statement, using a simple ternary operation is straightforward. Let’s say we have a website where users can make an account. Once users sign in, we want to give them a custom greeting. We can create a basic function to do this using the ternary operator.

This function takes a condition called signedIn , which is a true or false value that relates to whether a user has logged into their account. If the condition is true, the ternary operator returns a personalized greeting. If the condition is false, it returns a generic greeting.

This is a neat way of writing simple logic. If we used an if/else statement instead of a ternary operation, the function would take up more space to achieve exactly the same result.

Evaluate Truthy/Falsy Conditions With Ternary Operator

Just like if/else statements in JavaScript, ternary expressions can evaluate truthy or falsy conditions. These conditions might return true or false values, but might also return other values that JavaScript coerces to be true or false. For example, if a condition returns null , NaN , 0 , an empty string ( “” ) or undefined , JavaScript will treat it as false in a ternary operation.

This behavior comes in handy when dealing with conditions that return missing values. We can use our custom greeting function from the previous example to show this. Giving this function a condition that returns null executes the “false” expression by default.

Although truthy and falsy conditions can be useful, they can also have unintended consequences. For example, we could assign a value of 1 or 0 to our condition signedIn . But a mistake in this assignment could result in signedIn having a NaN or undefined value. JavaScript would then treat the condition as false without any warning, which could lead to unexpected behavior.

To avoid situations like this, we can set conditions that test for exact values. If we only wanted to output a personalized greeting if signedIn has a value of 1 , we could write the following.

Using the Ternary Operator With Many Conditions

The ternary operator can also be an alternative to more complex if/else statements with several conditions. For example, we could check that members on our website are both signed in and have a paid membership before giving them a custom greeting. We can do this in a ternary operation by adding the extra condition using the && operator.

Again, this phrasing is more concise than an if/else statement. But we can go even further with the ternary operator by specifying multiple “else” conditions.

For instance, we could use the ternary operator to determine which stage of life a customer is in based on their age. If we wanted to classify users as children, teenagers, adults, or seniors, we could use the following function ternary operation:

Chaining together ternary operators like this saves plenty of space. Rewriting this function as a chain of if/else statements takes up around twice as many lines.

This is also an example where using if/else statements leads to less readable code. Although the ternary operator displays each condition and its corresponding return value in the same line, the if/else statement separates these pairings. This makes the logic of the if/else code harder to follow at a glance. If used within longer scripts, this might also make such code harder to debug, giving further reason to use the ternary operator.

Strengths and Limitations of the Ternary Operator

As seen above, the ternary operator in JavaScript has many strengths as an alternative to if/else statements.

Strengths of the Ternary Operator in JavaScript

It can represent conditional statements more concisely than if/else statements
In cases where conditions and return values are simple, ternary operator statements are easier to read than if/else statements
As a longstanding feature of JavaScript, it has excellent cross-browser compatibility

Yet there are situations where programmers should avoid using the ternary operator.

Limitations of the Ternary Operator in JavaScript

Conditional statements with longer expressions can be hard to read with the ternary operator’s inline syntax. These expressions could otherwise be split across many lines in an if/else statement, resulting in better readability.
Nested conditions are also better expressed as if/else statements than with the ternary operator. Although you can nest conditional statements with the ternary operator, the result is often messy and hard to debug. If/else statements lend themselves better to nested conditions because they are split over many lines. This visual separation makes each condition easier to understand and maintain.

More in JavaScript 8 Common JavaScript Data Structures

Start Using the Ternary Operator in JavaScript

In summary, the ternary operator is a great way of phrasing conditional statements. Although it isn’t suited to dense expressions or nested conditions, it can still replace long if/else statements with shorter, more readable code. Though not to be overused, it is still essential knowledge for any accomplished JavaScript programmer.

Recent Software Engineering Articles

Javascript inline if Syntax And Usage With Example Program

In this article, we will analyze the concept of JavaScript inline if and discuss its usage and benefits.

Basically, one of the powerful features of JavaScript is the ability to write conditional statements, which allow programmers to execute different blocks of code based on specific conditions.

Among these conditional statements, the “inline if” or the ternary operator is a popular choice for writing concise and efficient code.

What is Javascript inline if?

The JavaScript inline if , also known as the ternary operator, is a concise way to write conditional statements.

It provides a compact syntax for evaluating a condition and choosing one of two expressions based on the result.

This inline if statement is often used as a shorthand alternative to traditional if-else statements when the logic is simple and the code needs to be concise.

Return Value

A condition in programming is a logical expression that can be true or false. When the condition is true, the code before the colon (:) is executed, while the code after the colon is executed when the condition is false.

Example Programs of inline if statement javascript

Basic usage.

Let’s start with a basic example to illustrate the usage of the JavaScript inline if:

Nested Ternary Operators

The JavaScript inline if statements can be nested to handle more complex conditions.

Here’s an example:

Assigning Values Conditionally

Consider the following example:

Best Practices for Using JavaScript Inline If

Readability and clarity.

When using the ternary operator, it’s crucial to write code that is easy to read and understand.

Avoiding Complex Nesting

When the logic becomes complex, consider using traditional if-else statements instead.

Combining with Other Operators

Advantages of javascript inline if.

The JavaScript inline if offers several advantages:

Disadvantages of JavaScript Inline If

By following best practices and avoiding excessive nesting, you can leverage the advantages of the JavaScript inline if to write clean and efficient code.

How to write an inline IF statement in JavaScript?

Conditional statements are the most important and basic concept of any programming language. The if-else statement allows us to execute any code block conditionally. We can define the condition for the if statement in braces, and if the condition becomes true, it executes the code of the if block; Otherwise, it executes the code of the else block.

Here, we have demonstrated how an if-else statement works in JavaScript.

From the above code, users can learn the syntax of if-else statements.

What if I say that you can write the above five lines of code into one line? Yes, you can do that using the inline if statement.

Users can follow the syntax below to use the inline if statement in JavaScript.

In the above syntax, a condition is an expression. When the condition expression evaluates true, it executes code block 1; Otherwise, it executes code block 2.

If we compare the inline if statement with the if-else statement, code-block-1 is a code of the if statement and code-block-2 is a code of the else statement.

In the example below, we will learn the basic use of the inline if statement. We have used the condition ‘10===10’, and if the condition evaluates true, it will print that ’10 is equal to 10’; Otherwise, it will print that ’10 is not equal to 10’.

In the output, users can observe that it prints ’10 is equal to 10’ as the condition always evaluates true.

In the example below, we have created the array of numbers. Also, we have created the func1() and func2() function, which prints the different messages with the value passed as a parameter.

We used the forEach() method to loop through the array. In the callback function of the forEach() method, we check that if the number is divisible by 10, call the func1() function; Otherwise, call the func2() function.

In the example below, we check whether the year is a leap year or not using an if-else statement and an inline if statement. The checkYear() function uses the if-else statements to ensure whether the year passed as a parameter is a leap year.

In the checkInlineYear() function, we have implemented the same logic as in the checkYear() function, but we have converted the if-else statements into the inline if statement. Users can see how we have written the nine lines in a single line.

Users can observe that both functions give the same output for any year value.

Users learned to use the inline if statement in JavaScript. We can observe that inline if statements make code clearer and more readable, and it is always good to write fewer lines of code with the same logic.

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Conditional branching: if, '?'

Sometimes, we need to perform different actions based on different conditions.

To do that, we can use the if statement and the conditional operator ? , that’s also called a “question mark” operator.

The “if” statement

The if(...) statement evaluates a condition in parentheses and, if the result is true , executes a block of code.

For example:

In the example above, the condition is a simple equality check ( year == 2015 ), but it can be much more complex.

If we want to execute more than one statement, we have to wrap our code block inside curly braces:

We recommend wrapping your code block with curly braces {} every time you use an if statement, even if there is only one statement to execute. Doing so improves readability.

Boolean conversion

The if (…) statement evaluates the expression in its parentheses and converts the result to a boolean.

Let’s recall the conversion rules from the chapter Type Conversions :

A number 0 , an empty string "" , null , undefined , and NaN all become false . Because of that they are called “falsy” values.
Other values become true , so they are called “truthy”.

So, the code under this condition would never execute:

…and inside this condition – it always will:

We can also pass a pre-evaluated boolean value to if , like this:

The “else” clause

The if statement may contain an optional else block. It executes when the condition is falsy.

Several conditions: “else if”

Sometimes, we’d like to test several variants of a condition. The else if clause lets us do that.

In the code above, JavaScript first checks year < 2015 . If that is falsy, it goes to the next condition year > 2015 . If that is also falsy, it shows the last alert .

There can be more else if blocks. The final else is optional.

Conditional operator ‘?’

Sometimes, we need to assign a variable depending on a condition.

For instance:

The so-called “conditional” or “question mark” operator lets us do that in a shorter and simpler way.

The operator is represented by a question mark ? . Sometimes it’s called “ternary”, because the operator has three operands. It is actually the one and only operator in JavaScript which has that many.

The syntax is:

The condition is evaluated: if it’s truthy then value1 is returned, otherwise – value2 .

Technically, we can omit the parentheses around age > 18 . The question mark operator has a low precedence, so it executes after the comparison > .

This example will do the same thing as the previous one:

But parentheses make the code more readable, so we recommend using them.

In the example above, you can avoid using the question mark operator because the comparison itself returns true/false :

Multiple ‘?’

A sequence of question mark operators ? can return a value that depends on more than one condition.

It may be difficult at first to grasp what’s going on. But after a closer look, we can see that it’s just an ordinary sequence of tests:

The first question mark checks whether age < 3 .
If true – it returns 'Hi, baby!' . Otherwise, it continues to the expression after the colon “:”, checking age < 18 .
If that’s true – it returns 'Hello!' . Otherwise, it continues to the expression after the next colon “:”, checking age < 100 .
If that’s true – it returns 'Greetings!' . Otherwise, it continues to the expression after the last colon “:”, returning 'What an unusual age!' .

Here’s how this looks using if..else :

Non-traditional use of ‘?’

Sometimes the question mark ? is used as a replacement for if :

Depending on the condition company == 'Netscape' , either the first or the second expression after the ? gets executed and shows an alert.

We don’t assign a result to a variable here. Instead, we execute different code depending on the condition.

It’s not recommended to use the question mark operator in this way.

The notation is shorter than the equivalent if statement, which appeals to some programmers. But it is less readable.

Here is the same code using if for comparison:

Our eyes scan the code vertically. Code blocks which span several lines are easier to understand than a long, horizontal instruction set.

The purpose of the question mark operator ? is to return one value or another depending on its condition. Please use it for exactly that. Use if when you need to execute different branches of code.

if (a string with zero)

Will alert be shown?

Yes, it will.

Any string except an empty one (and "0" is not empty) becomes true in the logical context.

We can run and check:

The name of JavaScript

Using the if..else construct, write the code which asks: ‘What is the “official” name of JavaScript?’

If the visitor enters “ECMAScript”, then output “Right!”, otherwise – output: “You don’t know? ECMAScript!”

Demo in new window

Show the sign

Using if..else , write the code which gets a number via prompt and then shows in alert :

1 , if the value is greater than zero,
-1 , if less than zero,
0 , if equals zero.

In this task we assume that the input is always a number.

Rewrite 'if' into '?'

Rewrite this if using the conditional operator '?' :

Rewrite 'if..else' into '?'

Rewrite if..else using multiple ternary operators '?' .

For readability, it’s recommended to split the code into multiple lines.

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Home » JavaScript Tutorial » JavaScript Ternary Operator

JavaScript Ternary Operator

Summary : in this tutorial, you will learn how to use the JavaScript ternary operator to make your code more concise.

Introduction to JavaScript ternary operator

When you want to execute a block if a condition evaluates to true , you often use an if…else statement. For example:

In this example, we show a message that a person can drive if the age is greater than or equal to 16. Alternatively, you can use a ternary operator instead of the if-else statement like this:

Or you can use the ternary operator in an expression as follows:

Here’s the syntax of the ternary operator:

In this syntax, the condition is an expression that evaluates to a Boolean value, either true or false .

If the condition is true , the first expression ( expresionIfTrue ) executes. If it is false, the second expression ( expressionIfFalse ) executes.

The following shows the syntax of the ternary operator used in an expression:

In this syntax, if the condition is true , the variableName will take the result of the first expression ( expressionIfTrue ) or expressionIfFalse otherwise.

JavaScript ternary operator examples

Let’s take some examples of using the ternary operator.

1) Using the JavaScript ternary operator to perform multiple statements

The following example uses the ternary operator to perform multiple operations, where each operation is separated by a comma. For example:

In this example, the returned value of the ternary operator is the last value in the comma-separated list.

2) Simplifying ternary operator example

See the following example:

If the locked is 1, then the canChange variable is set to false , otherwise, it is set to true . In this case, you can simplify it by using a Boolean expression as follows:

3) Using multiple JavaScript ternary operators example

The following example shows how to use two ternary operators in the same expression:

It’s a good practice to use the ternary operator when it makes the code easier to read. If the logic contains many if...else statements, you should avoid using the ternary operators.

Use the JavaScript ternary operator ( ?: )to make the code more concise.

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Conditional Statements in JavaScript

JavaScript conditional statements allow you to execute specific blocks of code based on conditions. If the condition is met, a particular block of code will run; otherwise, another block of code will execute based on the condition.

There are several methods that can be used to perform Conditional Statements in JavaScript.

Conditional Statement	Description
if statement	Executes a block of code if a specified condition is true.
else statement	Executes a block of code if the same condition of the preceding if statement is false.
else if statement	Adds more conditions to the if statement, allowing for multiple alternative conditions to be tested.
switch statement	Evaluates an expression, then executes the case statement that matches the expression’s value.
ternary operator	Provides a concise way to write if-else statements in a single line.
Nested if else statement	Allows for multiple conditions to be checked in a hierarchical manner.

This table outlines the key characteristics and use cases of each type of conditional statement. Now let’s understand each conditional statement in detail along with the examples.

JavaScript Conditional statements Examples:

1. using if statement.

The if statement is used to evaluate a particular condition. If the condition holds true, the associated code block is executed.

Example: In this example, we are using the if statement to find given number is even or odd.

Explanation: This JavaScript code determines if the variable `num` is even or odd using the modulo operator `%`. If `num` is divisible by 2 without a remainder, it logs “Given number is even number.” Otherwise, it logs “Given number is odd number.”

2. Using if-else Statement

The if-else statement will perform some action for a specific condition. Here we are using the else statement in which the else statement is written after the if statement and it has no condition in their code block.

Example: In this example, we are using if-else conditional statement to check the driving licence eligibility date.

Explanation: This JavaScript code checks if the variable `age` is greater than or equal to 18. If true, it logs “You are eligible for a driving license.” Otherwise, it logs “You are not eligible for a driving license.” This indicates eligibility for driving based on age.

3. else if Statement

The else if statement in JavaScript allows handling multiple possible conditions and outputs, evaluating more than two options based on whether the conditions are true or false.

Example: In this example, we are using the above-explained approach.

Explanation: This JavaScript code determines whether the constant `num` is positive, negative, or zero. If `num` is greater than 0, it logs “Given number is positive.” If `num` is less than 0, it logs “Given number is negative.” If neither condition is met (i.e., `num` is zero), it logs “Given number is zero.”

4. Using Switch Statement (JavaScript Switch Case)

As the number of conditions increases, you can use multiple else-if statements in JavaScript. but when we dealing with many conditions, the switch statement may be a more preferred option.

Example: In this example, we find a branch name Based on the student’s marks, this switch statement assigns a specific engineering branch to the variable Branch. The output displays the student’s branch name,

Explanation:

This JavaScript code assigns a branch of engineering to a student based on their marks. It uses a switch statement with cases for different mark ranges. The student’s branch is determined according to their marks and logged to the console.

5. Using Ternary Operator ( ?: )

The conditional operator, also referred to as the ternary operator (?:), is a shortcut for expressing conditional statements in JavaScript.

Example: In this example, we use the ternary operator to check if the user’s age is 18 or older. It prints eligibility for voting based on the condition.

Explanation: This JavaScript code checks if the variable `age` is greater than or equal to 18. If true, it assigns the string “You are eligible to vote.” to the variable `result`. Otherwise, it assigns “You are not eligible to vote.” The value of `result` is then logged to the console.

6. Nested if…else

Nested if…else statements in JavaScript allow us to create complex conditional logic by checking multiple conditions in a hierarchical manner. Each if statement can have an associated else block, and within each if or else block, you can nest another if…else statement. This nesting can continue to multiple levels, but it’s important to maintain readability and avoid excessive complexity.

Example: This example demonstrates how nested if…else statements can be used to handle different scenarios based on multiple conditions.

Explanation: In this example, the outer if statement checks the weather variable. If it’s “sunny,” it further checks the temperature variable to determine the type of day it is (hot, warm, or cool). Depending on the values of weather and temperature, different messages will be logged to the console.

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JS Reference

Html events, html objects, other references, javascript if...else.

If the hour is less than 20, output "Good day":

Output "Good day" or "Good evening":

More examples below.

Description

The if/else statement executes a block of code if a specified condition is true. If the condition is false, another block of code can be executed.

The if/else statement is a part of JavaScript's "Conditional" Statements, which are used to perform different actions based on different conditions.

In JavaScript we have the following conditional statements:

Use if to specify a block of code to be executed, if a specified condition is true
Use else to specify a block of code to be executed, if the same condition is false
Use else if to specify a new condition to test, if the first condition is false
Use switch to select one of many blocks of code to be executed

The if statement specifies a block of code to be executed if a condition is true:

The else statement specifies a block of code to be executed if the condition is false:

The else if statement specifies a new condition if the first condition is false:

Parameter Values

Parameter	Description
	Required. An expression that evaluates to true or false

More Examples

If time is less than 10:00, create a "Good morning" greeting, if not, but time is less than 20:00, create a "Good day" greeting, otherwise a "Good evening":

If the first <div> element in the document has an id of "myDIV", change its font-size:

Change the value of the source attribute (src) of an <img> element, if the user clicks on the image:

Display a message based on user input:

Validate input data:

JavaScript Tutorial: JavaScript If...Else Statements

JavaScript Tutorial: JavaScript Switch Statement

Browser Support

if...else is an ECMAScript1 (ES1) feature.

ES1 (JavaScript 1997) is fully supported in all browsers:


Chrome	Edge	Firefox	Safari	Opera	IE
Yes	Yes	Yes	Yes	Yes	Yes

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Can I omit the else in an inline javascript if statement?

I'm trying to use this and it doesn't appear to be working. I'm guessing it's just not an option, but want to confirm. Is this valid?

No, it's not optional. Use a binary operator instead (&&) as long as thats_cool() returns a value that evaluates to true . – Jonathan M Commented Feb 10, 2012 at 18:35
Nope. It needs to have the : and some value following it. If you want, you could just create a function named do_nothing() that...well, does nothing. – Edwin Commented Feb 10, 2012 at 18:37
1 user1048967, That is called if() {} . – Dykam Commented Feb 10, 2012 at 18:37
@Jonathan It doesn't have to return boolean, as it'll be called if if_it_is evaluates to a truthy statement. – Edwin Commented Feb 10, 2012 at 18:41
Dykam - I guess I will have to resort to typing the extra keystroke. wishful thinking I guess! – evan Commented Feb 11, 2012 at 7:52

7 Answers 7

You can use && there:

It is basically equal to:

Nice. You can do null coalescence with or's. var variable2 = variable1 || 'coalesceVal'; – Jason Commented Feb 10, 2012 at 18:39
2 this is clever but it doesn't seem very intuitive to me. It doesn't read well. A question mark, I get. That, no. – evan Commented Feb 11, 2012 at 7:53
@user1048967: People coming from other languages find it hard, but this is actually beauty and terseness of javascript you need to learn. At first at looks strange to everyone like I myself was confused but now using it effectively. – Sarfraz Commented Feb 11, 2012 at 8:48
I'm still sad that there's no way to inline a conditional return statement other than if(x) return y; because you can't put a return statement in that nor the ternary expression. – Domino Commented Apr 14, 2015 at 0:15
using jshint it keeps saying that Expected an assignment or function call and instead saw an expression. (W030) source: 'jshint' – Muhammad Omer Aslam Commented Oct 9, 2017 at 8:10

What you are trying to use is a Ternary Operator . You are missing the else part of it.

You could do something like:

Or, as others have suggested, you can avoid the ternary if you don't care about the else.

In JavaScript, as well as most languages, these logical checks step from left to right. So it will first see if if_it_is is a 'trusy' value ( true , 1 , a string other than '' , et cetera). If that doesn't pass then it doesn't do the rest of the statement. If it does pass then it will execute thats_cool as the next check in the logic.

Think of it as the part inside of an if statement. Without the if. So it's kind of a shorthand of

Like your answer. It tells a story :) – Nebulosar Commented Jun 1, 2018 at 7:44

No, it's not valid.

The conditional operator takes the form x ? y : z . The third operand is not like the else in an if , it always has to be there.

You can't accomplish that using the ternary operator, but you can use the short-circuit nature of && to do what you want.

No, you can't. ?: is a ternary operator and MUST have all three of its operands.

No, you can't. It's not an "inline if statement", it's the ternary operator , and that is, well… ternary.

Since you do not seem to be interested in the return value of the operation, you could just write:

though. That would also be better style than using a ternary.

You miss the third component. Should be something like that:

The whole sense is:

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COMMENTS

Conditional (ternary) operator
The conditional (ternary) operator is the only JavaScript operator that takes three operands: a condition followed by a question mark (?), then an expression to execute if the condition is truthy followed by a colon (:), and finally the expression to execute if the condition is falsy. This operator is frequently used as an alternative to an if ...
How to write an inline IF statement in JavaScript?
If you just want an inline IF (without the ELSE), you can use the logical AND operator: (a < b) && /*your code*/; If you need an ELSE also, use the ternary operation that the other people suggested. edited Jul 15, 2015 at 20:31. answered Jul 14, 2015 at 3:51. Nahn.
Mastering the JavaScript Inline If: Ternary Operator Like a Pro
Transcoding February 3, 2024. Hey there, fellow coders! Today, we're diving into the nitty-gritty of JavaScript's inline if, also known as the ternary operator. This little gem is like a Swiss Army knife for your code, offering a sleek and efficient way to handle conditional logic.
Quick Tip: How to Use the Ternary Operator in JavaScript
It can be used to assign a value to a variable based on a condition, or execute an expression based on a condition. Syntax The ternary operator accepts three operands; it's the only operator in ...
Mastering JavaScript Inline If Statements: A Complete 2021 Guide
The ternary operator is ideal for quick inline conditional checks and assignments. For longer conditional flows, standard if statements are often preferable. Inline If using Logical && Along with the ternary operator, we can also use JavaScript's logical AND (&&) for inline conditionals. Here is an example:
Inline if Statement in JavaScript
Inline if Statement With Logical Operator in JavaScript. In this practice, a given condition that satisfies the return value is written after the (&&) operator. And if it is directed to the else condition, the return value is set after the || operator. Let's see the demonstration with a code example. Code Snippet:
How to write an inline IF statement in JavaScript
Method 1: In this method we write an inline IF statement Without else, only by using the statement given below. Syntax: // Your code here. Example: Below is the implementation of above approach: Output: Method 2: In this method, we will use ternary operator to write inline if statement. Syntax: If condition is true then value1 will be assigned ...
How to Use the Ternary Operator in JavaScript
In this example, I used the ternary operator to determine whether a user's age is greater than or equal to 18. Firstly, I used the prompt() built-in JavaScript function. This function opens a dialog box with the message What is your age? and the user can enter a value. I store the user's input in the age variable.
Write an Inline IF Statement in JavaScript (with code)
1) Using Ternary Operators. The best way to write an inline IF statement in Javascript is by using Ternary Operator. The ternary operator is denoted by a question mark (?) and a colon (:), allowing for concise conditional logic and action.
conditional operator
Ternary operator ?: used as inline if-else is right associative. In short this means that the rightmost ? gets fed first and it takes exactly one closest operand on the left and two , with a : , on the right.
Making decisions in your code
Here we've got: The keyword switch, followed by a set of parentheses.; An expression or value inside the parentheses. The keyword case, followed by a choice that the expression/value could be, followed by a colon.; Some code to run if the choice matches the expression. A break statement, followed by a semicolon. If the previous choice matches the expression/value, the browser stops executing ...
Ternary Operator in JavaScript Explained
The ternary operator gets its name by being the only operator in JavaScript that takes three operands, or parts. The first part of a ternary operation is a logical condition that returns a true or false value. Then, after a question mark, come two expressions, separated by a colon. The first is an expression to execute if the logical condition ...
Javascript inline if Syntax And Usage With Example Program
The JavaScript inline if, also known as the ternary operator, is a concise way to write conditional statements. It provides a compact syntax for evaluating a condition and choosing one of two expressions based on the result. This inline if statement is often used as a shorthand alternative to traditional if-else statements when the logic is ...
How to write an inline IF statement in JavaScript?
Users can follow the syntax below to use the inline if statement in JavaScript. Condition? code - block - 1 : code - block - 2. In the above syntax, a condition is an expression. When the condition expression evaluates true, it executes code block 1; Otherwise, it executes code block 2. If we compare the inline if statement with the if-else ...
Conditional branching: if,
In the code above, JavaScript first checks year < 2015. If that is falsy, it goes to the next condition year > 2015. If that is also falsy, it shows the last alert. There can be more else if blocks. The final else is optional. Conditional operator '?' Sometimes, we need to assign a variable depending on a condition. For instance:
Make Your Code Cleaner with JavaScript Ternary Operator
console .log(message); Code language: JavaScript (javascript) Here's the syntax of the ternary operator: In this syntax, the condition is an expression that evaluates to a Boolean value, either true or false. If the condition is true, the first expression ( expresionIfTrue) executes. If it is false, the second expression ( expressionIfFalse ...
Conditional Statements in JavaScript
There are several methods that can be used to perform Conditional Statements in JavaScript. Executes a block of code if a specified condition is true. Executes a block of code if the same condition of the preceding if statement is false. Adds more conditions to the if statement, allowing for multiple alternative conditions to be tested.
assign and execute if/else conditions in single line
15. You can use java ternary operator, this statement can be read as, If testCondition is true, assign the value of value1 to result; otherwise, assign the value of value2 to result. simple example would be, In above code, if the variable a is less than b, minVal is assigned the value of a; otherwise, minVal is assigned the value of b.
JavaScript if/else Statement
The if/else statement executes a block of code if a specified condition is true. If the condition is false, another block of code can be executed. The if/else statement is a part of JavaScript's "Conditional" Statements, which are used to perform different actions based on different conditions. In JavaScript we have the following conditional ...
Can I omit the else in an inline javascript if statement?
if_it_is && thats_cool(); In JavaScript, as well as most languages, these logical checks step from left to right. So it will first see if if_it_is is a 'trusy' value ( true, 1, a string other than '', et cetera). If that doesn't pass then it doesn't do the rest of the statement. If it does pass then it will execute thats_cool as the next check ...

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Performance Considerations

Debugging Ternary Operators

Conclusion: The Ternary Operator Is Your Friend (With Benefits)

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Wrapping Up

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Important Subjects

Making decisions in your code — conditionals

You can have it on one condition!

if...else statements

Basic if...else syntax

A real example

A note on comparison operators

Nesting if...else

Logical operators: AND, OR and NOT

switch statements

A switch example

Ternary operator