JavaScript Assignment
JavaScript Assignment Operators
Assignment operators assign values to JavaScript variables.
Given that x = 10 and y = 5, the table below explains the assignment operators:
| Operator | Example | Same As | Result |
|---|---|---|---|
| = | x = y | x = y | x = 5 |
| += | x += y | x = x + y | x = 15 |
| -= | x -= y | x = x - y | x = 5 |
| *= | x *= y | x = x * y | x = 50 |
| **= | x **= y | x = x ** y | x = 1000 |
| /= | x /= y | x = x / y | x = 2 |
| %= | x %= y | x = x % y | x = 0 |
| : | x: 45 | size.x = 45 | x = 45 |
Logical Assignment Operators
| Operator | Example | Result |
|---|---|---|
| &&= | true &&= 10 | x = 10 |
| ||= | false ||= 10 | x = 10 |
| ??= | null ??= 10 | x = 10 |
The = Operator
The Simple Assignment Operator assigns a value to a variable.
The += Operator
The Addition Assignment Operator adds a value to a variable.
Addition Assignment Examples
let x = 10;
x += 5;
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let text = "Hello";
text += " World";
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The -= Operator
The Subtraction Assignment Operator subtracts a value from a variable.
The *= Operator
The Multiplication Assignment Operator multiplies a variable.
The **= Operator
The Exponentiation Assignment Operator raises a variable to the power of the operand.
The /= Operator
The Division Assignment Operator divides a variable.
The %= Operator
The Remainder Assignment Operator assigns a remainder to a variable.
Logical Assignment Operators
| Operator | Example | Result |
|---|---|---|
| &&= | true &&= 10 | x = 10 |
| ||= | false ||= 10 | x = 10 |
| ??= | null ??= 10 | x = 10 |
The &&= Operator
The Logical AND assignment operator is used between two values.
If the first value is true, the second value is assigned.
Logical AND Assignment Examples
let x = true;
let y = x &&= 10;
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let x = false;
let y = x &&= 10;
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let x = 1;
let y = x &&= 10;
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let x = 0;
let y = x &&= 10;
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let x = undefined;
let y = x &&= 10;
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let x = null;
let y = x &&= 10;
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Note
The &&= operator is an ES2020 feature.
The ||= Operator
The Logical OR assignment operator is used between two values.
If the first value is false, the second value is assigned.
Logical OR Assignment Examples
let x = false;
let y = x ||= 10;
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let x = true;
let y = x ||= 10;
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let x = null;
let y = x ||= 10;
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let x = undefined;
let y = x ||= 10;
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Note
The ||= operator is an ES2020 feature.
The ??= Operator
The Nullish coalescing assignment operator is used between two values.
If the first value is undefined or null, the second value is assigned.
Nullish Coalescing Assignment Examples
let x;
x ??= 10;
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let x = 0;
x ??= 10;
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let x = null;
x ??= 10;
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let x = undefined;
x ??= 10;
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The ??= operator is an ES2020 feature.
The Conditional (Ternary) Operator
The conditional operator assigns a value to a variable based on a condition.
Syntax
(condition) ? value1:value2
If the variable age is a value below 18, the value of the variable voteable will be "Too young", otherwise the value of voteable will be "Old enough".
The Spread (...) Operator
The ... operator splits iterables into individual elements.
Example
let text = "12345";
let min = Math.min(...text);
let max = Math.max(...text);
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