How to Use the Assignment Operator in JavaScript

The Assignment operator is used to assign a value to a variable.

Assignment (=)

The assignment operator simply assigns the value of the right operand to the variable specified by the left operand.

let y = 5;

In the example above, let y is assigned the numeric value 5.

It is possible to assign any data type to a variable (e.g. String; Object; Function; etc.).

Assignments can be chained, allowing you to assign the value of the right operand to multiple variables in sequence.

The example code below demonstrates both the basic usage of the assignment operator, as well as the chaining functionality it enables:

let x = 5;
let y = 6;
let z = 7;
let a = 9;
x = y = z = a;
console.log(x, y, z, a);
// Expected output: 9 9 9 9

The example above defines four variables – x, y, z, and a – each with a different numeric value.

The fifth line of code assigns the value of the fourth variable (a, which contains the value 9) to the first three variables (x, y, and z). After this assignment, all four variables store the same numeric value – that of let a (9).

Other assignment operators

There are multiple types of assignment operators in JavaScript, in addition to the basic assignment operator detailed above:

Addition assignment (+=)

Subtraction assignment (-=)

Multiplication assignment (*=)

Division assignment (/=)

Remainder assignment (%=)

Exponentiation assignment (**=)

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