Decrement (--)

The decrement operator (--) decrements (subtracts one from) its operand and returns a value.

Syntax

Operator: x-- or --x

Description

If used postfix, with operator after operand (for example, x--), the decrement operator decrements and returns the value before decrementing.

If used prefix, with operator before operand (for example, --x), the decrement operator decrements and returns the value after decrementing.

Examples

Postfix decrement

let x = 3;
y = x--;

// y = 3
// x = 2

Prefix decrement

let a = 2;
b = --a;

// a = 1
// b = 1

Specifications

Specification
ECMAScript Language Specification (ECMAScript)
# sec-postfix-decrement-operator

Browser compatibility

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See also