Javascript Ternary Operator

This tutorial will help you learn how to replace an if/else statement with a more concise shorthand syntax called the ternary operator.

The conditional operator – also known as the ternary operator – is an alternative form of the if/else statement that helps you to write conditional code blocks in a more concise way.

The syntax for the conditional operator looks like this:

conditional ? expression_when_true : expression_when_false;

conditional operator basic syntax

First, you need to write a conditional expression that evaluates into either true or false. If the expression returns true, JavaScript will execute the code you write on the left side of the colon operator (:) when it returns false, the code on the right side of the colon operator is executed.

To understand how it works, let's compare it with a regular if/else statement. Let's say you have a small program that assigns different exam grades depending on your exam score:

• When you have a score higher than 80, you assign "A" as the grade.
• Else, you assign "B" as the grade.

Here's one way to write the program:

let score = 85;
let grade;
if(score >= 80){
    grade = "A";
} else {
    grade = "B";
}

console.log(`Your exam grade is ${grade}`);

A regular if/else statement

Alternatively, you can write the above code using the ternary operator as follows:

let score = 85;
let grade = score >= 80 ? "A" : "B";

console.log(`Your exam grade is ${grade}`);

A ternary operator replacing if/else statement

And there you go. The ternary operator shorthand looks way more concise and shorter than a regular if/else statement.

But what if your code requires multiple if/else statements? What if you add "C" and "D" grades into the evaluation?

let score = 85;
let grade;
if(score >= 80){
    grade = "A";
} else if (score >= 70) {
    grade = "B";
} else if (score >= 60) {
    grade = "C";
} else {
    grade = "D";
}

console.log(`Your exam grade is ${grade}`);

Multiple if/else statements in a program

No worries! You can write multiple ternary operators to replace the code above like this:

let score = 85;
let grade = score >= 80 ? "A" 
  : score >= 70 ? "B" 
  : score >= 60 ? "C" 
  : "D";

console.log(`Your exam grade is ${grade}`);

Multiple ternary operators in action

However, it's not recommended to replace multiple if/else statements with multiple ternary operators because it makes the code harder to read in the future. It's best to stick with either if/else or switch statements for such cases.