Check if a number is negative

Return true for numbers below zero.

JavaScript Version 1.0.0 · MIT · .md

function isNegative(n) { return n < 0; }

Input & expected output

-3

true

The edge case

0

false

Know the limits

• -0 is not negative here, matching n < 0.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Check whether all values are equal — Compare every item with the first using Object.is.
• Check whether an object is empty — Check for own enumerable string keys on a JSON object.
• Check whether an integer is even — Test parity for safe integers, including zero and negative values.