Unary negation (-)

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

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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.


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


ECMAScript Language Specification
# sec-unary-minus-operator

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See also