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39 lines
1.2 KiB
TypeScript
39 lines
1.2 KiB
TypeScript
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
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// This module is browser compatible.
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/**
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* Returns an array that drops all elements in the given iterable until the
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* last element that does not match the given predicate.
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*
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* @typeParam T The type of the elements in the input array.
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*
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* @param iterable The iterable to drop elements from.
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* @param predicate The function to test each element for a condition.
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*
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* @returns An array that drops all elements until the last element that does
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* not match the given predicate.
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*
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* @example Basic usage
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* ```ts
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* import { dropLastWhile } from "@std/collections/unstable-drop-last-while";
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* import { assertEquals } from "@std/assert";
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*
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* const numbers = [11, 42, 55, 20, 33, 44];
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*
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* const notFortyFour = dropLastWhile(numbers, (number) => number > 30);
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*
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* assertEquals(notFortyFour, [11, 42, 55, 20]);
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* ```
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*/
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export function dropLastWhile<T>(
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iterable: Iterable<T>,
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predicate: (el: T) => boolean,
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): T[] {
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const array = Array.isArray(iterable) ? iterable : Array.from(iterable);
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let offset = array.length - 1;
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while (offset >= 0 && predicate(array[offset]!)) {
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offset--;
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}
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return array.slice(0, offset + 1);
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}
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