JavaScript Assignment Operators
Assignment operators are used to assign values to variables in JavaScript.
// Lets take some variables
x = 10
y = 20
x = y // Here, x is equal to 20
console.log(x);
console.log(y);
Output
20 20
More Assignment Operators
There are so many assignment operators as shown in the table with the description.
| OPERATOR NAME | SHORTHAND OPERATOR | MEANING |
|---|---|---|
| Addition Assignment | a+=b | a=a+b |
| Subtraction Assignment | a-=b | a=a-b |
| Multiplication Assignment | a*=b | a=a*b |
| Division Assignment | a/=b | a=a/b |
| Remainder Assignment | a%=b | a=a%b |
| Exponentiation Assignment | a**=b | a=a**b |
| Left Shift Assignment | a<<=b | a=a<<b |
| Right Shift Assignment | a>>=b | a=a>>b |
| Bitwise AND Assignment | a&=b | a=a&b |
| Bitwise OR Assignment | a|=b | a=a | b |
| Bitwise XOR Assignment | a^=b | a=a^b |
a&&=b | x && (x = y) | |
|
||= | x || (x = y) | |
|
??= | x ?? (x = y) |
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 + 1);
Output
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(foo = yoo - 1);
Output
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 yoo = 4;
// Expected output 3
console.log(foo = yoo - 1);
Output
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 yoo = 10;
const moo = 2;
// Expected output 5
console.log(yoo = yoo / moo);
// Expected output Infinity
console.log(yoo /= 0);
Output
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 yoo = 50;
// Expected output 0
console.log(yoo %= 10);
Output
0
Exponentiation Assignment Operator
The Exponentiation Assignment Operator raises the value of a variable to the power of the right operand.
Example:
let yoo = 50;
// Expected output 0
console.log(yoo %= 10);
Output
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 yoo = 5;
// Expected output 20(In Binary 10100)
console.log(yoo <<= 2);
Output
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 yoo = 5;
// Expected Output 1(In binary 001)
console.log(yoo >>= 2);
Output
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 yoo = 5;
// Expected output 0(In binary 000)
console.log(yoo &= 2);
Output
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 yoo=5;
// Expected output 7(In binary 111)
console.log(yoo|=2);
Output
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 yoo = 5;
// Expected output 7(In binary 111)
console.log(yoo ^= 2);
Output
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);
// Changing the value using logical
// AND assignment operator
name.firstName &&= "Shyam";
// Here the value changed because
// name.firstName is truthy
console.log(name.firstName);
console.log(name.lastName);
// Changing the value using logical
// AND assignment operator
name.lastName &&= "Kumar";
// Here the value remains unchanged
// because name.lastName is falsy
console.log(name.lastName);
Output
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 name = {
firstName: "Ram",
lastName: "",
};
console.log(name.firstName);
// Changing the value using logical
// OR assignment operator
name.firstName ||= "Shyam";
// But value does not change because
// name.firstName is truthy
console.log(name.firstName);
console.log(name.lastName);
// Changing the value using logical
// OR assignment operator
name.lastName ||= "Kumar";
// The value changes because name.lastName is falsy
console.log(name.lastName);
Output
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 x = 12;
let y = null;
let z = 13;
// The value of x will become
// unchanged because x is not nullish.
x ??= z;
// The value of y will be
// changed because y is nullish.
y ??= z;
console.log(x) // 12
console.log(y) // 13
Output
12 13
Supported Browsers: The browsers supported by all JavaScript Assignment operators are listed below:
