Check whether an integer is even

Test parity for safe integers, including zero and negative values.

JavaScript Version 1.0.0 · MIT · .md

function isEven(value) { return value % 2 === 0; }

Input & expected output

42

true

The edge case

-4

true

Know the limits

• The input must be a safe integer. Fractional values are rejected.

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 a leap year — Apply the Gregorian divisible-by-4, century and 400-year rules.