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Unary negation (-)

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The unary negation (-) operator precedes its operand and negates it.

In this article

Try it

const x = 4; const y = -x; console.log(y); // Expected output: -4 const a = "4"; const b = -a; console.log(b); // Expected output: -4

Syntax

js
-x

Description

The - operator is overloaded for two types of operands: number and BigInt. It first coerces the operand to a numeric value and tests the type of it. It performs BigInt negation if the operand becomes a BigInt; otherwise, it performs number negation.

Examples

Negating numbers

js
const x = 3; const y = -x; // y is -3; x is 3

Negating non-numbers

The unary negation operator can convert a non-number into a number.

js
const x = "4"; const y = -x; // y is -4

BigInts can be negated using the unary negation operator.

js
const x = 4n; const y = -x; // y is -4n

Specifications

Specification
ECMAScript® 2027 Language Specification
# sec-unary-minus-operator

Browser compatibility

Enable JavaScript to view this browser compatibility table.

See also

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  1. JavaScript
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    71. SyntaxError: nothing to repeat
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    91. SyntaxError: Using //@ to indicate sourceURL pragmas is deprecated. Use //# instead
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    113. TypeError: cyclic object value
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  14. Misc
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