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std/collections/partition.ts

The Deno Standard Library
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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * Returns a tuple of two arrays with the first one containing all elements in * the given array that match the given predicate and the second one containing * all that do not. * * @example * ```ts * import { partition } from "https://deno.land/std@$STD_VERSION/collections/partition.ts"; * import { assertEquals } from "https://deno.land/std@$STD_VERSION/assert/assert_equals.ts"; * * const numbers = [5, 6, 7, 8, 9]; * const [even, odd] = partition(numbers, (it) => it % 2 === 0); * * assertEquals(even, [6, 8]); * assertEquals(odd, [5, 7, 9]); * ``` */export function partition<T>( array: Iterable<T>, predicate: (el: T) => boolean,): [T[], T[]];/** * Returns a tuple of two arrays with the first one containing all elements in * the given array that match the given predicate and the second one containing * all that do not. * * @example * ```ts * import { partition } from "https://deno.land/std@$STD_VERSION/collections/partition.ts"; * import { assertEquals } from "https://deno.land/std@$STD_VERSION/assert/assert_equals.ts"; * * const numbers = [5, 6, 7, 8, 9]; * const [even, odd] = partition(numbers, (it) => it % 2 === 0); * * assertEquals(even, [6, 8]); * assertEquals(odd, [5, 7, 9]); * ``` */export function partition<T, U extends T>( array: Iterable<T>, predicate: (el: T) => el is U,): [U[], Exclude<T, U>[]];export function partition( array: Iterable<unknown>, predicate: (el: unknown) => boolean,): [unknown[], unknown[]] { const matches: Array<unknown> = []; const rest: Array<unknown> = [];
for (const element of array) { if (predicate(element)) { matches.push(element); } else { rest.push(element); } }
return [matches, rest];}