for...in

Baseline
Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The for...in statement iterates over all enumerable string properties of an object (ignoring properties keyed by symbols), including inherited enumerable properties.

Try it

const object = { a: 1, b: 2, c: 3 };

for (const property in object) {
  console.log(`${property}: ${object[property]}`);
}

// Expected output:
// "a: 1"
// "b: 2"
// "c: 3"

Syntax

js
for (variable in object)
  statement

Parameters