How to use JavaScript Assignment Operators - Assignment Operators Explained

Assignment Operators

Assignment operators, as the name suggests, assign (or re-assign) values to a variable. While there are quite a few variations of 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

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 usually shorthand methods for performing standard operations using the variable (indicated by x above) and value (indicated by y above) and then assigning 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: 5 + 7 = 12

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