87 lines
1.8 KiB
JavaScript
87 lines
1.8 KiB
JavaScript
/**
|
|
* Copyright (c) 2013-present, Facebook, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* This source code is licensed under the BSD-style license found in the
|
|
* LICENSE file in the root directory of this source tree. An additional grant
|
|
* of patent rights can be found in the PATENTS file in the same directory.
|
|
*
|
|
* @polyfill
|
|
*/
|
|
|
|
/* eslint-disable */
|
|
|
|
/**
|
|
* Creates an array from array like objects.
|
|
*
|
|
* https://people.mozilla.org/~jorendorff/es6-draft.html#sec-array.from
|
|
*/
|
|
if (!Array.from) {
|
|
Array.from = function(arrayLike /*, mapFn, thisArg */) {
|
|
if (arrayLike == null) {
|
|
throw new TypeError('Object is null or undefined');
|
|
}
|
|
|
|
// Optional args.
|
|
var mapFn = arguments[1];
|
|
var thisArg = arguments[2];
|
|
|
|
var C = this;
|
|
var items = Object(arrayLike);
|
|
var symbolIterator = typeof Symbol === 'function'
|
|
? Symbol.iterator
|
|
: '@@iterator';
|
|
var mapping = typeof mapFn === 'function';
|
|
var usingIterator = typeof items[symbolIterator] === 'function';
|
|
var key = 0;
|
|
var ret;
|
|
var value;
|
|
|
|
if (usingIterator) {
|
|
ret = typeof C === 'function'
|
|
? new C()
|
|
: [];
|
|
var it = items[symbolIterator]();
|
|
var next;
|
|
|
|
while (!(next = it.next()).done) {
|
|
value = next.value;
|
|
|
|
if (mapping) {
|
|
value = mapFn.call(thisArg, value, key);
|
|
}
|
|
|
|
ret[key] = value;
|
|
key += 1;
|
|
}
|
|
|
|
ret.length = key;
|
|
return ret;
|
|
}
|
|
|
|
var len = items.length;
|
|
if (isNaN(len) || len < 0) {
|
|
len = 0;
|
|
}
|
|
|
|
ret = typeof C === 'function'
|
|
? new C(len)
|
|
: new Array(len);
|
|
|
|
while (key < len) {
|
|
value = items[key];
|
|
|
|
if (mapping) {
|
|
value = mapFn.call(thisArg, value, key);
|
|
}
|
|
|
|
ret[key] = value;
|
|
|
|
key += 1;
|
|
}
|
|
|
|
ret.length = key;
|
|
return ret;
|
|
};
|
|
}
|