38 lines
1.4 KiB
JavaScript
38 lines
1.4 KiB
JavaScript
import { take as take$1 } from "../../array/take.mjs";
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import { combineEagerAndLazyFunctions, createLazyFunction } from "../_internal/lazy.mjs";
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//#region src/fp/array/take.ts
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/**
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* Creates a function that returns the first `count` elements of an array. If
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* `count` is greater than the array length, the whole array is returned. Use it
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* with {@link pipe}.
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*
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* The returned function is **lazy-capable** for a non-negative integer `count`:
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* inside a {@link pipe} it stops the walk as soon as `count` elements have been
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* collected, so preceding lazy functions never process the rest of the input.
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*
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* @template T - The type of elements in the array.
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* @param count - The number of elements to take from the front of the array.
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* @returns A function that maps a `readonly T[]` to a new `T[]`.
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*
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* @example
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* import { pipe, take } from 'es-toolkit/fp';
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*
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* pipe([1, 2, 3, 4, 5], take(3)); // => [1, 2, 3]
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*
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* @example
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* // Early termination: `map` only runs three times.
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* pipe([1, 2, 3, 4, 5], map(expensive), take(3));
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*/
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function take(count) {
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function takeEager(array) {
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return take$1(array, count);
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}
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if (!Number.isInteger(count) || count < 0) return takeEager;
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return combineEagerAndLazyFunctions(takeEager, createLazyFunction((value, index, emit) => {
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if (index >= count) return false;
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emit(value);
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return index < count - 1;
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}), { shortCircuit: true });
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}
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//#endregion
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export { take };
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