Vielzeug

Appearance

flatten ​

Problem ​

You have a nested array and need to collapse it into a flat list, optionally controlling how many levels deep to flatten.

Solution ​

Use flatten(array, depth?) to recursively flatten. Default depth is 1.

ts
import { flatten } from '@vielzeug/arsenal';

flatten([
  [1, 2],
  [3, [4, 5]],
]); // [1, 2, 3, [4, 5]]
flatten(
  [
    [1, 2],
    [3, [4, 5]],
  ],
  2,
); // [1, 2, 3, 4, 5]
flatten([[[1]], [[2]]], Infinity); // [1, 2]

Pitfalls ​

  • depth: 1 (default) only flattens one level. Pass Infinity for fully recursive flattening.
  • Does not flatten non-array values — plain objects and other iterables are left as-is.