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