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@stdlib/utils

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Standard 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 { Collection } from '@stdlib/types/array'; /** * Returns the first index at which a given element can be found. * * ## Notes * * - Search is performed using **strict equality** comparison. * * @param arr - array-like object * @param searchElement - element to find * @param fromIndex - starting index (if negative, the start index is determined relative to last element) * @throws `fromIndex` must be an integer * @returns index or -1 * * @example * var arr = [ 4, 3, 2, 1 ]; * var idx = indexOf( arr, 3 ); * // returns 1 * * @example * var arr = [ 4, 3, 2, 1 ]; * var idx = indexOf( arr, 5 ); * // returns -1 * * @example * // Using a `fromIndex`: * var arr = [ 1, 2, 3, 4, 5, 2, 6 ]; * var idx = indexOf( arr, 2, 3 ); * // returns 5 * * @example * // `fromIndex` which exceeds `array` length: * var arr = [ 1, 2, 3, 4, 2, 5 ]; * var idx = indexOf( arr, 2, 10 ); * // returns -1 * * @example * // Negative `fromIndex`: * var arr = [ 1, 2, 3, 4, 5, 2, 6, 2 ]; * var idx = indexOf( arr, 2, -4 ); * // returns 5 * * idx = indexOf( arr, 2, -1 ); * // returns 7 * * @example * // Negative `fromIndex` exceeding input `array` length: * var arr = [ 1, 2, 3, 4, 5, 2, 6 ]; * var idx = indexOf( arr, 2, -10 ); * // returns 1 * * @example * // Array-like objects: * var str = 'bebop'; * var idx = indexOf( str, 'o' ); * // returns 3 */ declare function indexOf( arr: Collection, searchElement: any, fromIndex?: number ): number; // EXPORTS // export = indexOf;