Ternary Operator :::: javascript

 Ternary Operator ::::  JavaScript

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 a shortcut for the if statement

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function getFee(isMember) {

  return (isMember ? '$2.00' : '$10.00');

}

console.log(getFee(true));

// expected output: "$2.00"

console.log(getFee(false));

// expected output: "$10.00"

console.log(getFee(null));

// expected output: "$10.00"

Syntax

condition ? exprIfTrue : exprIfFalse

Parameters

condition

An expression whose value is used as a condition.

exprIfTrue

An expression which is evaluated if the condition evaluates to a truthy value (one which equals or can be converted to true).

exprIfFalse

An expression which is executed if the condition is falsy (that is, has a value which can be converted to false).

Description

Besides false, possible falsy expressions are: null, NaN, 0, the empty string (""), and undefined. If condition is any of these, the result of the conditional expression will be the result of executing the expression exprIfFalse.

Examples

A simple example

var age = 26;
var beverage = (age >= 21) ? "Beer" : "Juice";
console.log(beverage); // "Beer"

Handling null values

One common usage is to handle a value that may be null:

let greeting = person => {
    let name = person ? person.name : `stranger`
    return `Howdy, ${name}`
}

console.log(greeting({name: `Alice`}));  // "Howdy, Alice"
console.log(greeting(null));             // "Howdy, stranger"

Conditional chains

The ternary operator is right-associative, which means it can be "chained" in the following way, similar to an if … else if … else if … else chain:

function example(…) {
    return condition1 ? value1
         : condition2 ? value2
         : condition3 ? value3
         : value4;
}

// Equivalent to:

function example(…) {
    if (condition1) { return value1; }
    else if (condition2) { return value2; }
    else if (condition3) { return value3; }
    else { return value4; }
}

Specifications

Specification
ECMAScript (ECMA-262) The definition of 'Conditional Operator' in that specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
Conditional operator (c ? t : f)	Full support1	Full support12	Full support1	Full support3	Full support3	Full support1	Full support1	Full support18	Full support4	Full support10.1	Full support1	Full support1.0	Full support0.1.100