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1var clone = (function() {
2'use strict';
3
4/**
5 * Clones (copies) an Object using deep copying.
6 *
7 * This function supports circular references by default, but if you are certain
8 * there are no circular references in your object, you can save some CPU time
9 * by calling clone(obj, false).
10 *
11 * Caution: if `circular` is false and `parent` contains circular references,
12 * your program may enter an infinite loop and crash.
13 *
14 * @param `parent` - the object to be cloned
15 * @param `circular` - set to true if the object to be cloned may contain
16 *    circular references. (optional - true by default)
17 * @param `depth` - set to a number if the object is only to be cloned to
18 *    a particular depth. (optional - defaults to Infinity)
19 * @param `prototype` - sets the prototype to be used when cloning an object.
20 *    (optional - defaults to parent prototype).
21*/
22function clone(parent, circular, depth, prototype) {
23  var filter;
24  if (typeof circular === 'object') {
25    depth = circular.depth;
26    prototype = circular.prototype;
27    filter = circular.filter;
28    circular = circular.circular
29  }
30  // maintain two arrays for circular references, where corresponding parents
31  // and children have the same index
32  var allParents = [];
33  var allChildren = [];
34
35  var useBuffer = typeof Buffer != 'undefined';
36
37  if (typeof circular == 'undefined')
38    circular = true;
39
40  if (typeof depth == 'undefined')
41    depth = Infinity;
42
43  // recurse this function so we don't reset allParents and allChildren
44  function _clone(parent, depth) {
45    // cloning null always returns null
46    if (parent === null)
47      return null;
48
49    if (depth == 0)
50      return parent;
51
52    var child;
53    var proto;
54    if (typeof parent != 'object') {
55      return parent;
56    }
57
58    if (clone.__isArray(parent)) {
59      child = [];
60    } else if (clone.__isRegExp(parent)) {
61      child = new RegExp(parent.source, __getRegExpFlags(parent));
62      if (parent.lastIndex) child.lastIndex = parent.lastIndex;
63    } else if (clone.__isDate(parent)) {
64      child = new Date(parent.getTime());
65    } else if (useBuffer && Buffer.isBuffer(parent)) {
66      if (Buffer.allocUnsafe) {
67        // Node.js >= 4.5.0
68        child = Buffer.allocUnsafe(parent.length);
69      } else {
70        // Older Node.js versions
71        child = new Buffer(parent.length);
72      }
73      parent.copy(child);
74      return child;
75    } else {
76      if (typeof prototype == 'undefined') {
77        proto = Object.getPrototypeOf(parent);
78        child = Object.create(proto);
79      }
80      else {
81        child = Object.create(prototype);
82        proto = prototype;
83      }
84    }
85
86    if (circular) {
87      var index = allParents.indexOf(parent);
88
89      if (index != -1) {
90        return allChildren[index];
91      }
92      allParents.push(parent);
93      allChildren.push(child);
94    }
95
96    for (var i in parent) {
97      var attrs;
98      if (proto) {
99        attrs = Object.getOwnPropertyDescriptor(proto, i);
100      }
101
102      if (attrs && attrs.set == null) {
103        continue;
104      }
105      child[i] = _clone(parent[i], depth - 1);
106    }
107
108    return child;
109  }
110
111  return _clone(parent, depth);
112}
113
114/**
115 * Simple flat clone using prototype, accepts only objects, usefull for property
116 * override on FLAT configuration object (no nested props).
117 *
118 * USE WITH CAUTION! This may not behave as you wish if you do not know how this
119 * works.
120 */
121clone.clonePrototype = function clonePrototype(parent) {
122  if (parent === null)
123    return null;
124
125  var c = function () {};
126  c.prototype = parent;
127  return new c();
128};
129
130// private utility functions
131
132function __objToStr(o) {
133  return Object.prototype.toString.call(o);
134};
135clone.__objToStr = __objToStr;
136
137function __isDate(o) {
138  return typeof o === 'object' && __objToStr(o) === '[object Date]';
139};
140clone.__isDate = __isDate;
141
142function __isArray(o) {
143  return typeof o === 'object' && __objToStr(o) === '[object Array]';
144};
145clone.__isArray = __isArray;
146
147function __isRegExp(o) {
148  return typeof o === 'object' && __objToStr(o) === '[object RegExp]';
149};
150clone.__isRegExp = __isRegExp;
151
152function __getRegExpFlags(re) {
153  var flags = '';
154  if (re.global) flags += 'g';
155  if (re.ignoreCase) flags += 'i';
156  if (re.multiline) flags += 'm';
157  return flags;
158};
159clone.__getRegExpFlags = __getRegExpFlags;
160
161return clone;
162})();
163
164if (typeof module === 'object' && module.exports) {
165  module.exports = clone;
166}
167