You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

61 lines
1.6 KiB
JavaScript

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;