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166 lines
4.3 KiB
166 lines
4.3 KiB
var clone = (function() { |
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'use strict'; |
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/** |
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* Clones (copies) an Object using deep copying. |
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* |
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* This function supports circular references by default, but if you are certain |
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* there are no circular references in your object, you can save some CPU time |
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* by calling clone(obj, false). |
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* |
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* Caution: if `circular` is false and `parent` contains circular references, |
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* your program may enter an infinite loop and crash. |
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* |
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* @param `parent` - the object to be cloned |
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* @param `circular` - set to true if the object to be cloned may contain |
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* circular references. (optional - true by default) |
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* @param `depth` - set to a number if the object is only to be cloned to |
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* a particular depth. (optional - defaults to Infinity) |
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* @param `prototype` - sets the prototype to be used when cloning an object. |
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* (optional - defaults to parent prototype). |
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*/ |
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function clone(parent, circular, depth, prototype) { |
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var filter; |
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if (typeof circular === 'object') { |
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depth = circular.depth; |
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prototype = circular.prototype; |
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filter = circular.filter; |
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circular = circular.circular |
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} |
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// maintain two arrays for circular references, where corresponding parents |
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// and children have the same index |
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var allParents = []; |
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var allChildren = []; |
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var useBuffer = typeof Buffer != 'undefined'; |
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if (typeof circular == 'undefined') |
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circular = true; |
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if (typeof depth == 'undefined') |
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depth = Infinity; |
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// recurse this function so we don't reset allParents and allChildren |
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function _clone(parent, depth) { |
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// cloning null always returns null |
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if (parent === null) |
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return null; |
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if (depth == 0) |
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return parent; |
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var child; |
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var proto; |
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if (typeof parent != 'object') { |
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return parent; |
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} |
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if (clone.__isArray(parent)) { |
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child = []; |
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} else if (clone.__isRegExp(parent)) { |
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child = new RegExp(parent.source, __getRegExpFlags(parent)); |
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if (parent.lastIndex) child.lastIndex = parent.lastIndex; |
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} else if (clone.__isDate(parent)) { |
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child = new Date(parent.getTime()); |
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} else if (useBuffer && Buffer.isBuffer(parent)) { |
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if (Buffer.allocUnsafe) { |
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// Node.js >= 4.5.0 |
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child = Buffer.allocUnsafe(parent.length); |
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} else { |
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// Older Node.js versions |
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child = new Buffer(parent.length); |
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} |
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parent.copy(child); |
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return child; |
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} else { |
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if (typeof prototype == 'undefined') { |
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proto = Object.getPrototypeOf(parent); |
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child = Object.create(proto); |
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} |
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else { |
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child = Object.create(prototype); |
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proto = prototype; |
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} |
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} |
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if (circular) { |
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var index = allParents.indexOf(parent); |
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if (index != -1) { |
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return allChildren[index]; |
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} |
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allParents.push(parent); |
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allChildren.push(child); |
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} |
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for (var i in parent) { |
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var attrs; |
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if (proto) { |
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attrs = Object.getOwnPropertyDescriptor(proto, i); |
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} |
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if (attrs && attrs.set == null) { |
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continue; |
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} |
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child[i] = _clone(parent[i], depth - 1); |
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} |
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return child; |
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} |
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return _clone(parent, depth); |
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} |
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/** |
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* Simple flat clone using prototype, accepts only objects, usefull for property |
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* override on FLAT configuration object (no nested props). |
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* |
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* USE WITH CAUTION! This may not behave as you wish if you do not know how this |
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* works. |
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*/ |
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clone.clonePrototype = function clonePrototype(parent) { |
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if (parent === null) |
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return null; |
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var c = function () {}; |
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c.prototype = parent; |
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return new c(); |
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}; |
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// private utility functions |
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function __objToStr(o) { |
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return Object.prototype.toString.call(o); |
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}; |
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clone.__objToStr = __objToStr; |
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function __isDate(o) { |
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return typeof o === 'object' && __objToStr(o) === '[object Date]'; |
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}; |
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clone.__isDate = __isDate; |
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function __isArray(o) { |
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return typeof o === 'object' && __objToStr(o) === '[object Array]'; |
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}; |
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clone.__isArray = __isArray; |
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function __isRegExp(o) { |
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return typeof o === 'object' && __objToStr(o) === '[object RegExp]'; |
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}; |
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clone.__isRegExp = __isRegExp; |
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function __getRegExpFlags(re) { |
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var flags = ''; |
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if (re.global) flags += 'g'; |
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if (re.ignoreCase) flags += 'i'; |
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if (re.multiline) flags += 'm'; |
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return flags; |
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}; |
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clone.__getRegExpFlags = __getRegExpFlags; |
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return clone; |
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})(); |
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if (typeof module === 'object' && module.exports) { |
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module.exports = clone; |
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}
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