JavaScript Assignment Operators

Introduction

Assignment operators, as the name suggests, assign (or re-assign) values to a variable. While there are quite a few variations on the assignment operators, they all build off of the basic assignment operator.

Syntax

x = y;

      | Description                                   | Necessity

--------- | --------------------------------------------- | --------- x | Variable | Required = | Assignment operator | Required y | Value to assign to variable | Required

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Examples

let initialVar = 5;   // Variable initialization requires the use of an assignment operator

let newVar = 5;
newVar = 6;   // Variable values can be modified using an assignment operator

Variations

The other assignment operators are a shorthand for performing some operation using the variable (indicated by x above) and value (indicated by y above) and then assinging the result to the variable itself.

For example, below is the syntax for the addition assignment operator:

x += y;

This is the same as applying the addition operator and reassigning the sum to the original variable (i.e., x), which can be expressed by the following code:

x = x + y;

To illustrate this using actual values, here is another example of using the addition assignment operator:

let myVar = 5;   // value of myVar: 5
myVar += 7;   // value of myVar: 12 = 5 + 7

Complete list of Javascript's assignment operators

Operator	Syntax	Long version
Assignment	x = y	x = y
Addition assignment	x += y	x = x + y
Subtraction assignment	x -= y	x = x - y
Multiplication assignment	x *= y	x = x * y
Division assignment	x /= y	x = x / y
Remainder assignment	x %= y	x = x % y
Exponentiation assignment	x **= y	x = x ** y
Left shift assignment	x <<= y	x = x << y
Right shift assignment	x >>= y	x = x >> y
Unsigned right shift assignment	x >>>= y	x = x >>> y
Bitwise AND assignment	x &= y	x = x & y
Bitwise XOR assignment	x ^= y	x = x ^ y
Bitwise OR assignment	x	= y