clone.js
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define(['../internal/baseClone', '../internal/bindCallback', '../internal/isIterateeCall'], function(baseClone, bindCallback, isIterateeCall) {
/**
* Creates a clone of `value`. If `isDeep` is `true` nested objects are cloned,
* otherwise they are assigned by reference. If `customizer` is provided it's
* invoked to produce the cloned values. If `customizer` returns `undefined`
* cloning is handled by the method instead. The `customizer` is bound to
* `thisArg` and invoked with up to three argument; (value [, index|key, object]).
*
* **Note:** This method is loosely based on the
* [structured clone algorithm](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm).
* The enumerable properties of `arguments` objects and objects created by
* constructors other than `Object` are cloned to plain `Object` objects. An
* empty object is returned for uncloneable values such as functions, DOM nodes,
* Maps, Sets, and WeakMaps.
*
* @static
* @memberOf _
* @category Lang
* @param {*} value The value to clone.
* @param {boolean} [isDeep] Specify a deep clone.
* @param {Function} [customizer] The function to customize cloning values.
* @param {*} [thisArg] The `this` binding of `customizer`.
* @returns {*} Returns the cloned value.
* @example
*
* var users = [
* { 'user': 'barney' },
* { 'user': 'fred' }
* ];
*
* var shallow = _.clone(users);
* shallow[0] === users[0];
* // => true
*
* var deep = _.clone(users, true);
* deep[0] === users[0];
* // => false
*
* // using a customizer callback
* var el = _.clone(document.body, function(value) {
* if (_.isElement(value)) {
* return value.cloneNode(false);
* }
* });
*
* el === document.body
* // => false
* el.nodeName
* // => BODY
* el.childNodes.length;
* // => 0
*/
function clone(value, isDeep, customizer, thisArg) {
if (isDeep && typeof isDeep != 'boolean' && isIterateeCall(value, isDeep, customizer)) {
isDeep = false;
}
else if (typeof isDeep == 'function') {
thisArg = customizer;
customizer = isDeep;
isDeep = false;
}
return typeof customizer == 'function'
? baseClone(value, isDeep, bindCallback(customizer, thisArg, 3))
: baseClone(value, isDeep);
}
return clone;
});