baseClone.js
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define(['./arrayCopy', './arrayEach', './baseAssign', './baseForOwn', './initCloneArray', './initCloneByTag', './initCloneObject', '../lang/isArray', './isHostObject', '../lang/isObject'], function(arrayCopy, arrayEach, baseAssign, baseForOwn, initCloneArray, initCloneByTag, initCloneObject, isArray, isHostObject, isObject) {
/** Used as a safe reference for `undefined` in pre-ES5 environments. */
var undefined;
/** `Object#toString` result references. */
var argsTag = '[object Arguments]',
arrayTag = '[object Array]',
boolTag = '[object Boolean]',
dateTag = '[object Date]',
errorTag = '[object Error]',
funcTag = '[object Function]',
mapTag = '[object Map]',
numberTag = '[object Number]',
objectTag = '[object Object]',
regexpTag = '[object RegExp]',
setTag = '[object Set]',
stringTag = '[object String]',
weakMapTag = '[object WeakMap]';
var arrayBufferTag = '[object ArrayBuffer]',
float32Tag = '[object Float32Array]',
float64Tag = '[object Float64Array]',
int8Tag = '[object Int8Array]',
int16Tag = '[object Int16Array]',
int32Tag = '[object Int32Array]',
uint8Tag = '[object Uint8Array]',
uint8ClampedTag = '[object Uint8ClampedArray]',
uint16Tag = '[object Uint16Array]',
uint32Tag = '[object Uint32Array]';
/** Used to identify `toStringTag` values supported by `_.clone`. */
var cloneableTags = {};
cloneableTags[argsTag] = cloneableTags[arrayTag] =
cloneableTags[arrayBufferTag] = cloneableTags[boolTag] =
cloneableTags[dateTag] = cloneableTags[float32Tag] =
cloneableTags[float64Tag] = cloneableTags[int8Tag] =
cloneableTags[int16Tag] = cloneableTags[int32Tag] =
cloneableTags[numberTag] = cloneableTags[objectTag] =
cloneableTags[regexpTag] = cloneableTags[stringTag] =
cloneableTags[uint8Tag] = cloneableTags[uint8ClampedTag] =
cloneableTags[uint16Tag] = cloneableTags[uint32Tag] = true;
cloneableTags[errorTag] = cloneableTags[funcTag] =
cloneableTags[mapTag] = cloneableTags[setTag] =
cloneableTags[weakMapTag] = false;
/** Used for native method references. */
var objectProto = Object.prototype;
/**
* Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
* of values.
*/
var objToString = objectProto.toString;
/**
* The base implementation of `_.clone` without support for argument juggling
* and `this` binding `customizer` functions.
*
* @private
* @param {*} value The value to clone.
* @param {boolean} [isDeep] Specify a deep clone.
* @param {Function} [customizer] The function to customize cloning values.
* @param {string} [key] The key of `value`.
* @param {Object} [object] The object `value` belongs to.
* @param {Array} [stackA=[]] Tracks traversed source objects.
* @param {Array} [stackB=[]] Associates clones with source counterparts.
* @returns {*} Returns the cloned value.
*/
function baseClone(value, isDeep, customizer, key, object, stackA, stackB) {
var result;
if (customizer) {
result = object ? customizer(value, key, object) : customizer(value);
}
if (result !== undefined) {
return result;
}
if (!isObject(value)) {
return value;
}
var isArr = isArray(value);
if (isArr) {
result = initCloneArray(value);
if (!isDeep) {
return arrayCopy(value, result);
}
} else {
var tag = objToString.call(value),
isFunc = tag == funcTag;
if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
if (isHostObject(value)) {
return object ? value : {};
}
result = initCloneObject(isFunc ? {} : value);
if (!isDeep) {
return baseAssign(result, value);
}
} else {
return cloneableTags[tag]
? initCloneByTag(value, tag, isDeep)
: (object ? value : {});
}
}
// Check for circular references and return its corresponding clone.
stackA || (stackA = []);
stackB || (stackB = []);
var length = stackA.length;
while (length--) {
if (stackA[length] == value) {
return stackB[length];
}
}
// Add the source value to the stack of traversed objects and associate it with its clone.
stackA.push(value);
stackB.push(result);
// Recursively populate clone (susceptible to call stack limits).
(isArr ? arrayEach : baseForOwn)(value, function(subValue, key) {
result[key] = baseClone(subValue, isDeep, customizer, key, value, stackA, stackB);
});
return result;
}
return baseClone;
});