JAVASCRIPT ASSIGNMENT OPERATORS

In this tutorial, you will learn about all the different assignment operators in javascript and how to use them in javascript.

Assignment Operators

In javascript, there are 16 different assignment operators that are used to assign value to the variable. It is shorthand of other operators which is recommended to use.

The assignment operators are used to assign value based on the right operand to its left operand.

The left operand must be a variable while the right operand may be a variable, number, boolean, string, expression, object, or combination of any other.

One of the most basic assignment operators is equal =, which is used to directly assign a value.

let a = 10;
console.log(a);

Assignment Operators List

Here is the list of all assignment operators in JavaScript:

In the following table if variable a is not defined then assume it to be 10.

Assignment operator

The assignment operator = is the simplest value assigning operator which assigns a given value to a variable.

let a = 10;
let b = "Hello World!";
console.log(a);
console.log(b);

The assignment operators support chaining, which means you can assign a single value in multiple variables in a single line.

let a, b, c;
a = b = c = 25;
console.log(a);
console.log(b);
console.log(c);

Addition assignment operator

The addition assignment operator += is used to add the value of the right operand to the value of the left operand and assigns the result to the left operand.

On the basis of the data type of variable, the addition assignment operator may add or concatenate the variables.

let a = 10;
let b = 'hello';
let c = true;
console.log(a += 20); // addition
console.log(b += ' world!'); // concatenation
console.log(c += true); // boolean + boolean -> addition

Subtraction assignment operator

The subtraction assignment operator -= subtracts the value of the right operand from the value of the left operand and assigns the result to the left operand.

If the value can not be subtracted then it results in a NaN.

let a = 10;
let b = 'hello';
let c = true;
console.log(a -= 20); // -10
console.log(b -= 'world'); // NaN
console.log(c -= true); // 0

Multiplication assignment operator

The multiplication assignment operator *= assigns the result to the left operand after multiplying values of the left and right operand.

let a = 10;
let b = 'hello';
let c = true;
console.log(a *= 2); // 20
console.log(b *= 5); // NaN
console.log(c *= true); // 1

Division assignment operator

The division assignment operator /= divides the value of the left operand by the value of the right operand and assigns the result to the left operand.

let a = 10;
let b = 'hello';
let c = true;
console.log(a /= 2); // 5
console.log(b /= 5); // NaN
console.log(c /= false); // Infinity

Remainder assignment operator

The remainder assignment operator %= assigns the remainder to the left operand after dividing the value of the left operand by the value of the right operand.

let a = 10;
let b = 'hello';
let c = true;
console.log(a %= 7); // 3
console.log(b %= 5); // NaN
console.log(c %= 1); // 0

Exponentiation assignment operator

The exponential assignment operator **= assigns the result of exponentiation to the left operand after exponentiating the value of the left operand by the value of the right operand.

let a = 10;
let b = 'hello';
let c = true;
console.log(a **= 3); // 100
console.log(b **= 5); // NaN
console.log(c **= 10); // 1

Left shift assignment

The left shift assignment operator <<= assigns the result of the left shift to the left operand after shifting the value of the left operand by the value of the right operand.

let a = 10;
// 10 = 00000000000000000000000000001010
let b = 2;
console.log(a <<= b);
console.log(a <<= 5);

Right shift assignment

The right shift assignment operator >>= assigns the result of the right shift to the left operand after shifting the value of the left operand by the value of the right operand.

let a = 10;
let b = 3;
console.log(a >>= 2);
console.log(b >>= 2);

Unsigned right shift assignment

The unsigned right shift assignment operator >>>= assigns the result of the unsigned right shift to the left operand after shifting the value of the left operand by the value of the right operand.

let a = 10;
let b = 3;
console.log(a >>>= 2);
console.log(b >>>= 2);

Bitwise AND assignment

The bitwise AND assignment operator &= assigns the result of bitwise AND to the left operand after ANDing the value of the left operand by the value of the right operand.

let a = 10;
let b = 3;
a &= b;
b &= 7;
console.log(a);
console.log(b);

Bitwise OR assignment

The bitwise OR assignment operator |= assigns the result of bitwise OR to the left operand after ORing the value of left operand by the value of the right operand.

let a = 10;
let b = 3;
a |= b;
b |= 5;
console.log(a);
console.log(b);

Bitwise XOR assignment

The bitwise XOR assignment operator ^= assigns the result of bitwise XOR to the left operand after XORing the value of the left operand by the value of the right operand.

let a = 10;
let b = 3;
a ^= b;
b ^= 5;
console.log(a);
console.log(b);

Logical AND assignment

The logical AND assignment operator &&= assigns value to left operand only when it is truthy.

Note: A truthy value is a value that is considered true when encountered in a boolean context.

let a = 2;
let b = "some string";
let c = false;
let d = 0;
console.log(a &&= 50); // assigned
console.log(b &&= "yes truthy"); // assigned
console.log(c &&= 23); // not assigned
console.log(d &&= 80); // not assigned

Logical OR assignment

The logical OR assignment operator ||= assigns value to left operand only when it is falsy.

Note: A falsy value is a value that is considered false when encountered in a boolean context.

let a = 2;
let b = "some string";
let c = false;
let d = 0;
console.log(a ||= 50); // not assigned
console.log(b ||= "truthy"); // not assigned
console.log(c ||= "yes falsy"); // assigned
console.log(d ||= 80); // assigned

Logical nullish assignment

The logical nullish assignment operator ??= assigns value to left operand only when it is nullish (null or undefined).

let a = null;
let b;
let c = 20;
let d = 0;
console.log(a ??= 50); // assigned
console.log(b ??= "hello world!"); // assigned
console.log(c ??= 100); // not assigned
console.log(d ??= 80); // not assigned