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@stdlib/iter

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Standard iterator utilities.

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/* * @license Apache-2.0 * * Copyright (c) 2019 The Stdlib Authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ // TypeScript Version: 4.1 /// <reference types="@stdlib/types"/> import { Iterator as Iter, IterableIterator } from '@stdlib/types/iter'; // Define a union type representing both iterable and non-iterable iterators: type Iterator = Iter | IterableIterator; /** * Returns an iterator which returns the first `n` values of a provided iterator. * * ## Notes * * - If a provided iterator only generates `m` values and `m` is less than `n`, the returned iterator only returns `m` values. * - If an environment supports `Symbol.iterator` **and** a provided iterator is iterable, the returned iterator is iterable. * * @param iterator - input iterator * @param n - number of values * @returns iterator * * @example * var randu = require( '@stdlib/random/iter/randu' ); * * var iter = iterHead( randu(), 10 ); * * var r = iter.next().value; * // returns <number> * * r = iter.next().value; * // returns <number> * * r = iter.next().value; * // returns <number> * * // ... */ declare function iterHead( iterator: Iterator, n: number ): Iterator; // EXPORTS // export = iterHead;