Unary negation (-)
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The unary negation (-) operator precedes its operand and negates it.
{{InteractiveExample("JavaScript Demo: Expressions - Unary negation operator")}}
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
-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
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.
const x = "4";
const y = -x;
// y is -4
BigInts can be negated using the unary negation operator.
const x = 4n;
const y = -x;
// y is -4n
Specifications
{{Specifications}}
Browser compatibility
{{Compat}}