Pick a random property of an object

Return one of the object’s own enumerable keys.

JavaScriptNode.js & browsers Version 1.0.0 · MIT · .md

function randomKey(object) { const keys = Object.keys(object); return keys[Math.floor(Math.random() * keys.length)]; }

Usage

const colors = { aqua: '#00ffff', azure: '#f0ffff', beige: '#f5f5dc' };
Object.hasOwn(colors, randomKey(colors)); // → true
randomKey({}); // → undefined

Lines marked → were executed in Node.js 22 and in headless Chromium, and each result was compared with the value shown. Lines marked e.g. are illustrative.

Know the limits

• Own enumerable string keys only; an empty object returns undefined. The original called Object.keys twice.

The function above is the code the usage lines run. It does not validate its arguments; add checks where it receives untrusted input.

Keep exploring

• Generate a random boolean — Return true or false with equal probability.
• Generate a random floating point number in given range — Scale Math.random into [min, max).
• Generate a random hex color — Return a #rrggbb color from 24 random bits.