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JavaScript Assignment


JavaScript Assignment Operators

Assignment operators assign values to JavaScript variables.

Given that x = 10 and y = 5, the table below explains the assignment operators:

Operator Example Same As Result
= x = y x = y x = 5
+= x += y x = x + y x = 15
-= x -= y x = x - y x = 5
*= x *= y x = x * y x = 50
**= x **= y x = x ** y x = 100000
/= x /= y x = x / y x = 2
%= x %= y x = x % y x = 0
: x: 45 size.x = 45 x = 45

Logical Assignment Operators

Operator Example Result
&&= true &&= 10 x = 10
||= false ||= 10 x = 10
??= null ??= 10 x = 10

The = Operator

The Simple Assignment Operator assigns a simple value to a variable.

Simple Assignment Examples

let x = 10;
Try it Yourself »
let x = 10 + y;
Try it Yourself »

The += Operator

The Addition Assignment Operator adds a value to a variable.

Addition Assignment Examples

let x = 10;
x += 5;
Try it Yourself »

The -= Operator

The Subtraction Assignment Operator subtracts a value from a variable.

Subtraction Assignment Example

let x = 10;
x -= 5;
Try it Yourself »

The *= Operator

The Multiplication Assignment Operator multiplies a variable.

Multiplication Assignment Example

let x = 10;
x *= 5;
Try it Yourself »

The **= Operator

The Exponentiation Assignment Operator raises a variable to the power of the operand.

Exponentiation Assignment Example

let x = 10;
x **= 5;
Try it Yourself »

The /= Operator

The Division Assignment Operator divides a variable.

Division Assignment Example

let x = 10;
x /= 5;
Try it Yourself »

The %= Operator

The Remainder Assignment Operator assigns a remainder to a variable.

Remainder Assignment Example

let x = 10;
x %= 5;
Try it Yourself »


String Assignment

Two assignment operators can assign values to strings:

The Simple Assignment Operator assigns a simple value to a string.

The Addition Assignment Operator adds a value to a string.


The = Operator

The Simple Assignment Operator assigns a value to a variable.

String Assignment

let text = "Hello";
Try it Yourself »

The += Operator

The Addition Assignment Operator Can also be used to add strings.

Addition Assignment Example

let text = "Hello"; text += " World";
Try it Yourself »

The &&= Operator

The Logical AND assignment operator is used between two values.

If the first value is true, the second value is assigned.

Logical AND Assignment Examples

let x = true;
let y = x &&= 10;
Try it Yourself »
let x = false;
let y = x &&= 10;
Try it Yourself »
let x = 1;
let y = x &&= 10;
Try it Yourself »
let x = 0;
let y = x &&= 10;
Try it Yourself »
let x = undefined;
let y = x &&= 10;
Try it Yourself »
let x = null;
let y = x &&= 10;
Try it Yourself »

Note

The &&= operator is an ES2020 feature.


The ||= Operator

The Logical OR assignment operator is used between two values.

If the first value is false, the second value is assigned.

Logical OR Assignment Examples

let x = false;
let y = x ||= 10;
Try it Yourself »
let x = true;
let y = x ||= 10;
Try it Yourself »
let x = null;
let y = x ||= 10;
Try it Yourself »
let x = undefined;
let y = x ||= 10;
Try it Yourself »

Note

The ||= operator is an ES2020 feature.


The ??= Operator

The Nullish coalescing assignment operator is used between two values.

If the first value is undefined or null, the second value is assigned.

Nullish Coalescing Assignment Examples

let x;
x ??= 10;
Try it Yourself »
let x = 0;
x ??= 10;
Try it Yourself »
let x = null;
x ??= 10;
Try it Yourself »
let x = undefined;
x ??= 10;
Try it Yourself »
let x = 10;
let y = 5;
x ??= y;
Try it Yourself »

Note

The ??= operator is an ES2020 feature.


The Spread (...) Operator

The ... operator splits iterables into individual elements.

Example

let text = "12345";

let min = Math.min(...text);
let max = Math.max(...text);
Try it Yourself »


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