var binaryIndex = require('../internal/binaryIndex'), indexOfNaN = require('../internal/indexOfNaN'); /* Native method references for those with the same name as other `lodash` methods. */ var nativeMax = Math.max, nativeMin = Math.min; /** * This method is like `_.indexOf` except that it iterates over elements of * `array` from right to left. * * @static * @memberOf _ * @category Array * @param {Array} array The array to search. * @param {*} value The value to search for. * @param {boolean|number} [fromIndex=array.length-1] 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 * * _.lastIndexOf([1, 2, 1, 2], 2); * // => 3 * * // using `fromIndex` * _.lastIndexOf([1, 2, 1, 2], 2, 2); * // => 1 * * // performing a binary search * _.lastIndexOf([1, 1, 2, 2], 2, true); * // => 3 */ function lastIndexOf(array, value, fromIndex) { var length = array ? array.length : 0; if (!length) { return -1; } var index = length; if (typeof fromIndex == 'number') { index = (fromIndex < 0 ? nativeMax(length + fromIndex, 0) : nativeMin(fromIndex || 0, length - 1)) + 1; } else if (fromIndex) { index = binaryIndex(array, value, true) - 1; var other = array[index]; if (value === value ? (value === other) : (other !== other)) { return index; } return -1; } if (value !== value) { return indexOfNaN(array, index, true); } while (index--) { if (array[index] === value) { return index; } } return -1; } module.exports = lastIndexOf;