| var baseIndexOf = require('../internal/baseIndexOf'), |
| binaryIndex = require('../internal/binaryIndex'); |
| |
| /* Native method references for those with the same name as other `lodash` methods. */ |
| var nativeMax = Math.max; |
| |
| /** |
| * Gets the index at which the first occurrence of `value` is found in `array` |
| * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero) |
| * for equality comparisons. If `fromIndex` is negative, it's used as the offset |
| * from the end of `array`. If `array` is sorted providing `true` for `fromIndex` |
| * performs a faster binary search. |
| * |
| * @static |
| * @memberOf _ |
| * @category Array |
| * @param {Array} array The array to search. |
| * @param {*} value The value to search for. |
| * @param {boolean|number} [fromIndex=0] The index to search from or `true` |
| * to perform a binary search on a sorted array. |
| * @returns {number} Returns the index of the matched value, else `-1`. |
| * @example |
| * |
| * _.indexOf([1, 2, 1, 2], 2); |
| * // => 1 |
| * |
| * // using `fromIndex` |
| * _.indexOf([1, 2, 1, 2], 2, 2); |
| * // => 3 |
| * |
| * // performing a binary search |
| * _.indexOf([1, 1, 2, 2], 2, true); |
| * // => 2 |
| */ |
| function indexOf(array, value, fromIndex) { |
| var length = array ? array.length : 0; |
| if (!length) { |
| return -1; |
| } |
| if (typeof fromIndex == 'number') { |
| fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : fromIndex; |
| } else if (fromIndex) { |
| var index = binaryIndex(array, value); |
| if (index < length && |
| (value === value ? (value === array[index]) : (array[index] !== array[index]))) { |
| return index; |
| } |
| return -1; |
| } |
| return baseIndexOf(array, value, fromIndex || 0); |
| } |
| |
| module.exports = indexOf; |