1/*
2object-assign
3(c) Sindre Sorhus
4@license MIT
5*/
6
7'use strict';
8/* eslint-disable no-unused-vars */
9var getOwnPropertySymbols = Object.getOwnPropertySymbols;
10var hasOwnProperty = Object.prototype.hasOwnProperty;
11var propIsEnumerable = Object.prototype.propertyIsEnumerable;
12
13function toObject(val) {
14	if (val === null || val === undefined) {
15		throw new TypeError('Object.assign cannot be called with null or undefined');
16	}
17
18	return Object(val);
19}
20
21function shouldUseNative() {
22	try {
23		if (!Object.assign) {
24			return false;
25		}
26
27		// Detect buggy property enumeration order in older V8 versions.
28
29		// https://bugs.chromium.org/p/v8/issues/detail?id=4118
30		var test1 = new String('abc');  // eslint-disable-line no-new-wrappers
31		test1[5] = 'de';
32		if (Object.getOwnPropertyNames(test1)[0] === '5') {
33			return false;
34		}
35
36		// https://bugs.chromium.org/p/v8/issues/detail?id=3056
37		var test2 = {};
38		for (var i = 0; i < 10; i++) {
39			test2['_' + String.fromCharCode(i)] = i;
40		}
41		var order2 = Object.getOwnPropertyNames(test2).map(function (n) {
42			return test2[n];
43		});
44		if (order2.join('') !== '0123456789') {
45			return false;
46		}
47
48		// https://bugs.chromium.org/p/v8/issues/detail?id=3056
49		var test3 = {};
50		'abcdefghijklmnopqrst'.split('').forEach(function (letter) {
51			test3[letter] = letter;
52		});
53		if (Object.keys(Object.assign({}, test3)).join('') !==
54				'abcdefghijklmnopqrst') {
55			return false;
56		}
57
58		return true;
59	} catch (err) {
60		// We don't expect any of the above to throw, but better to be safe.
61		return false;
62	}
63}
64
65module.exports = shouldUseNative() ? Object.assign : function (target, source) {
66	var from;
67	var to = toObject(target);
68	var symbols;
69
70	for (var s = 1; s < arguments.length; s++) {
71		from = Object(arguments[s]);
72
73		for (var key in from) {
74			if (hasOwnProperty.call(from, key)) {
75				to[key] = from[key];
76			}
77		}
78
79		if (getOwnPropertySymbols) {
80			symbols = getOwnPropertySymbols(from);
81			for (var i = 0; i < symbols.length; i++) {
82				if (propIsEnumerable.call(from, symbols[i])) {
83					to[symbols[i]] = from[symbols[i]];
84				}
85			}
86		}
87	}
88
89	return to;
90};
91