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| module.exports = extend;
|
| /*
| var obj = {a: 3, b: 5};
| extend(obj, {a: 4, c: 8}); // {a: 4, b: 5, c: 8}
| obj; // {a: 4, b: 5, c: 8}
|
| var obj = {a: 3, b: 5};
| extend({}, obj, {a: 4, c: 8}); // {a: 4, b: 5, c: 8}
| obj; // {a: 3, b: 5}
|
| var arr = [1, 2, 3];
| var obj = {a: 3, b: 5};
| extend(obj, {c: arr}); // {a: 3, b: 5, c: [1, 2, 3]}
| arr.push(4);
| obj; // {a: 3, b: 5, c: [1, 2, 3, 4]}
|
| var arr = [1, 2, 3];
| var obj = {a: 3, b: 5};
| extend(true, obj, {c: arr}); // {a: 3, b: 5, c: [1, 2, 3]}
| arr.push(4);
| obj; // {a: 3, b: 5, c: [1, 2, 3]}
|
| extend({a: 4, b: 5}); // {a: 4, b: 5}
| extend({a: 4, b: 5}, 3); {a: 4, b: 5}
| extend({a: 4, b: 5}, true); {a: 4, b: 5}
| extend('hello', {a: 4, b: 5}); // throws
| extend(3, {a: 4, b: 5}); // throws
| */
|
| function extend(/* [deep], obj1, obj2, [objn] */) {
| var args = [].slice.call(arguments);
| var deep = false;
| if (typeof args[0] == 'boolean') {
| deep = args.shift();
| }
| var result = args[0];
| if (isUnextendable(result)) {
| throw new Error('extendee must be an object');
| }
| var extenders = args.slice(1);
| var len = extenders.length;
| for (var i = 0; i < len; i++) {
| var extender = extenders[i];
| for (var key in extender) {
| if (Object.prototype.hasOwnProperty.call(extender, key)) {
| var value = extender[key];
| if (deep && isCloneable(value)) {
| var base = Array.isArray(value) ? [] : {};
| result[key] = extend(
| true,
| Object.prototype.hasOwnProperty.call(result, key) && !isUnextendable(result[key])
| ? result[key]
| : base,
| value
| );
| } else {
| result[key] = value;
| }
| }
| }
| }
| return result;
| }
|
| function isCloneable(obj) {
| return Array.isArray(obj) || {}.toString.call(obj) == '[object Object]';
| }
|
| function isUnextendable(val) {
| return !val || (typeof val != 'object' && typeof val != 'function');
| }
|
|
