JavaScript Assignment Operators

Assignment operators are used to assign values to variables in JavaScript.

// Lets take some variables
x = 10
y = 20
x = y ;
console.log(x);
console.log(y);

20
20

More Assignment Operators

There are so many assignment operators as shown in the table with the description.

Addition Assignment Operator(+=)

The Addition assignment operator adds the value to the right operand to a variable and assigns the result to the variable. Addition or concatenation is possible. In case of concatenation then we use the string as an operand.

Example:

let a = 2;
const b = 3;
// Expected output: 2
console.log(a);
// Expected output: 4
console.log(a += b );

2
4

Subtraction Assignment Operator(-=)

The Substraction Assignment Operator subtracts the value of the right operand from a variable and assigns the result to the variable.

Example:

let yoo = 4;
// Expected output 3
console.log(yoo -= 1); 

3

Multiplication Assignment Operator(*=)

The Multiplication Assignment operator multiplies a variable by the value of the right operand and assigns the result to the variable.

Example:

let yooMul = 4;
// Expected output 3
console.log(yooMul *= 2); 

3

Division Assignment Operator(/=)

The Division Assignment operator divides a variable by the value of the right operand and assigns the result to the variable.

Example:

let yooDiv = 10;
const moo = 2;
console.log(yooDiv /= moo);  
console.log(yooDiv /= 0); 

5
Infinity

Remainder Assignment Operator(%=)

The Remainder Assignment Operator divides a variable by the value of the right operand and assigns the remainder to the variable.

Example:

let yooRem = 50;
console.log(yooRem %= 10); 

0

Exponentiation Assignment Operator

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

Example:

let yooExp = 2;
console.log(yooExp **= 3);

0

Left Shift Assignment Operator(<<=)

This Left Shift Assignment Operator moves the specified amount of bits to the left and assigns the result to the variable.

Example:

let yooShiftLeft = 5;
console.log(yooShiftLeft <<= 2); 

20

Right Shift Assignment Operator(>>=)

The Right Shift Assignment Operator moves the specified amount of bits to the right and assigns the result to the variable.

Example:

let yooShiftRight = 5;
console.log(yooShiftRight >>= 2);

1

Bitwise AND Assignment Operator(&=)

The Bitwise AND Assignment Operator uses the binary representation of both operands, does a bitwise AND operation on them, and assigns the result to the variable.

Example:

let yooBitwiseAnd = 5;
console.log(yooBitwiseAnd &= 2);

0

Btwise OR Assignment Operator(|=)

The Btwise OR Assignment Operator uses the binary representation of both operands, does a bitwise OR operation on them, and assigns the result to the variable.

Example:

let yooBitwiseOr = 5;
console.log(yooBitwiseOr |= 2);

7

Bitwise XOR Assignment Operator(^=)

The Bitwise XOR Assignment Operator uses the binary representation of both operands, does a bitwise XOR operation on them, and assigns the result to the variable.

Example:

let yooBitwiseXor = 5;
console.log(yooBitwiseXor ^= 2); 

7

Logical AND Assignment Operator(&&=)

The Logical AND Assignment assigns the value of y into x only if x is a truthy value.

Example:

let name = { firstName: "Ram", lastName: "" };
console.log(name.firstName); 
name.firstName &&= "Shyam";
console.log(name.firstName);  
console.log(name.lastName);  
name.lastName &&= "Kumar";
console.log(name.lastName);  

Ram
Shyam

Logical OR Assignment Operator(||=)

The Logical OR Assignment Operator is used to assign the value of y to x if the value of x is falsy.

Example:

let nameOr = { firstName: "Ram", lastName: "" };
console.log(nameOr.firstName);  
nameOr.firstName ||= "Shyam";
console.log(nameOr.firstName);  
console.log(nameOr.lastName);  
nameOr.lastName ||= "Kumar";
console.log(nameOr.lastName);  

Ram
Ram
Kumar

Nullish coalescing Assignment Operator(??=)

The Nullish coalescing Assignment Operator assigns the value of y to x if the value of x is null.

Example:

let xNull = 12;
let yNull = null;
let zNull = 13;
xNull ??= zNull;
yNull ??= zNull;
console.log(xNull);  
console.log(yNull);  

12
13