array-iteration-from-last.js•1.2 kB
'use strict';
var bind = require('../internals/function-bind-context');
var IndexedObject = require('../internals/indexed-object');
var toObject = require('../internals/to-object');
var lengthOfArrayLike = require('../internals/length-of-array-like');
// `Array.prototype.{ findLast, findLastIndex }` methods implementation
var createMethod = function (TYPE) {
var IS_FIND_LAST_INDEX = TYPE === 1;
return function ($this, callbackfn, that) {
var O = toObject($this);
var self = IndexedObject(O);
var index = lengthOfArrayLike(self);
var boundFunction = bind(callbackfn, that);
var value, result;
while (index-- > 0) {
value = self[index];
result = boundFunction(value, index, O);
if (result) switch (TYPE) {
case 0: return value; // findLast
case 1: return index; // findLastIndex
}
}
return IS_FIND_LAST_INDEX ? -1 : undefined;
};
};
module.exports = {
// `Array.prototype.findLast` method
// https://github.com/tc39/proposal-array-find-from-last
findLast: createMethod(0),
// `Array.prototype.findLastIndex` method
// https://github.com/tc39/proposal-array-find-from-last
findLastIndex: createMethod(1)
};