time-to-botec

Benchmark sampling in different programming languages
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index_of.js (3171B)

      1 /**
      2 * @license Apache-2.0
      3 *
      4 * Copyright (c) 2018 The Stdlib Authors.
      5 *
      6 * Licensed under the Apache License, Version 2.0 (the "License");
      7 * you may not use this file except in compliance with the License.
      8 * You may obtain a copy of the License at
      9 *
     10 *    http://www.apache.org/licenses/LICENSE-2.0
     11 *
     12 * Unless required by applicable law or agreed to in writing, software
     13 * distributed under the License is distributed on an "AS IS" BASIS,
     14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     15 * See the License for the specific language governing permissions and
     16 * limitations under the License.
     17 */
     18 
     19 'use strict';
     20 
     21 // MODULES //
     22 
     23 var isnan = require( '@stdlib/assert/is-nan' );
     24 var isCollection = require( '@stdlib/assert/is-collection' );
     25 var isString = require( '@stdlib/assert/is-string' ).isPrimitive;
     26 var isInteger = require( '@stdlib/assert/is-integer' ).isPrimitive;
     27 
     28 
     29 // MAIN //
     30 
     31 /**
     32 * Returns the first index at which a given element can be found.
     33 *
     34 * @param {ArrayLike} arr - array-like object
     35 * @param {*} searchElement - element to find
     36 * @param {integer} [fromIndex] - starting index (if negative, the start index is determined relative to last element)
     37 * @throws {TypeError} must provide an array-like object
     38 * @throws {TypeError} `fromIndex` must be an integer
     39 * @returns {integer} index or -1
     40 *
     41 * @example
     42 * var arr = [ 4, 3, 2, 1 ];
     43 * var idx = indexOf( arr, 3 );
     44 * // returns 1
     45 *
     46 * @example
     47 * var arr = [ 4, 3, 2, 1 ];
     48 * var idx = indexOf( arr, 5 );
     49 * // returns -1
     50 *
     51 * @example
     52 * // Using a `fromIndex`:
     53 * var arr = [ 1, 2, 3, 4, 5, 2, 6 ];
     54 * var idx = indexOf( arr, 2, 3 );
     55 * // returns 5
     56 *
     57 * @example
     58 * // `fromIndex` which exceeds `array` length:
     59 * var arr = [ 1, 2, 3, 4, 2, 5 ];
     60 * var idx = indexOf( arr, 2, 10 );
     61 * // returns -1
     62 *
     63 * @example
     64 * // Negative `fromIndex`:
     65 * var arr = [ 1, 2, 3, 4, 5, 2, 6, 2 ];
     66 * var idx = indexOf( arr, 2, -4 );
     67 * // returns 5
     68 *
     69 * idx = indexOf( arr, 2, -1 );
     70 * // returns 7
     71 *
     72 * @example
     73 * // Negative `fromIndex` exceeding input `array` length:
     74 * var arr = [ 1, 2, 3, 4, 5, 2, 6 ];
     75 * var idx = indexOf( arr, 2, -10 );
     76 * // returns 1
     77 *
     78 * @example
     79 * // Array-like objects:
     80 * var str = 'bebop';
     81 * var idx = indexOf( str, 'o' );
     82 * // returns 3
     83 */
     84 function indexOf( arr, searchElement, fromIndex ) {
     85 	var len;
     86 	var i;
     87 	if ( !isCollection( arr ) && !isString( arr ) ) {
     88 		throw new TypeError( 'invalid argument. First argument must be an array-like object. Value: `' + arr + '`.' );
     89 	}
     90 	len = arr.length;
     91 	if ( len === 0 ) {
     92 		return -1;
     93 	}
     94 	if ( arguments.length === 3 ) {
     95 		if ( !isInteger( fromIndex ) ) {
     96 			throw new TypeError( 'invalid argument. `fromIndex` must be an integer. Value: `' + fromIndex + '`.' );
     97 		}
     98 		if ( fromIndex >= 0 ) {
     99 			if ( fromIndex >= len ) {
    100 				return -1;
    101 			}
    102 			i = fromIndex;
    103 		} else {
    104 			i = len + fromIndex;
    105 			if ( i < 0 ) {
    106 				i = 0;
    107 			}
    108 		}
    109 	} else {
    110 		i = 0;
    111 	}
    112 	// Check for `NaN`...
    113 	if ( isnan( searchElement ) ) {
    114 		for ( ; i < len; i++ ) {
    115 			if ( isnan( arr[i] ) ) {
    116 				return i;
    117 			}
    118 		}
    119 	} else {
    120 		for ( ; i < len; i++ ) {
    121 			if ( arr[ i ] === searchElement ) {
    122 				return i;
    123 			}
    124 		}
    125 	}
    126 	return -1;
    127 }
    128 
    129 
    130 // EXPORTS //
    131 
    132 module.exports = indexOf;