API reference › @evolu/common › Array › arrayFrom

Call Signature

function arrayFrom<T>(iterable: Iterable<T>): readonly T[];

Defined in: packages/common/src/Array.ts:259

Better Array.from.

  • Returns readonly arrays
  • Accepts length directly: arrayFrom(3, fn) instead of Array.from({ length: 3 }, fn)
  • Returns existing arrays unchanged

Creating from iterables and lengths

import { assertEqual, assertSame, assertType, arrayFrom } from "@evolu/common";

const fromSet = arrayFrom(new Set([1, 2, 3]));
assertEqual(fromSet, [1, 2, 3]);
assertType<ReadonlyArray<number>, typeof fromSet>();

assertEqual(
  arrayFrom(3, (i) => i * 10),
  [0, 10, 20],
);

const existing: ReadonlyArray<number> = [1, 2, 3];
assertSame(arrayFrom(existing), existing);

Unlike Array.from, there's no map parameter for iterables — use mapArray instead, or iterator helpers directly on iterables.

Call Signature

function arrayFrom<T>(length: number, map: (index: number) => T): readonly T[];

Defined in: packages/common/src/Array.ts:261

From length and map function.

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