Method cloneDeep

lib/util.js:518–590

* Return a deep copy of the specified object using cloneDeep(parent, depth, circular, prototype). * * This returns a new object with all elements copied from the specified * object. Deep copies are made of objects and arrays so you can do anything * with the returned object without affe

(parent, depth, circular, prototype)

   * notice shall be included in all copies or substantial portions of the Software.
   */
  static cloneDeep(parent, depth, circular, prototype) {
    // maintain two arrays for circular references, where corresponding parents
    // and children have the same index
    const allParents = [];
    const allChildren = [];
    const util = this;

    if (typeof circular === 'undefined')
      circular = true;

    if (typeof depth === 'undefined')
      depth = 20;

    // recurse this function so we don't reset allParents and allChildren
    function _clone(parent, depth) {
      // cloning null always returns null
      if (parent === null)
        return null;

      if (depth === 0)
        return parent;

      let child;
      if (typeof parent != 'object') {
        return parent;
      }

      if (Array.isArray(parent)) {
        child = [];
      } else if (parent instanceof RegExp) {
        child = new RegExp(parent.source, util.getRegExpFlags(parent));
        if (parent.lastIndex) child.lastIndex = parent.lastIndex;
      } else if (parent instanceof Date) {
        child = new Date(parent.getTime());
      } else if (Buffer.isBuffer(parent)) {
        child = Buffer.alloc(parent.length);
        parent.copy(child);
        return child;
      } else if (parent instanceof RawConfig) {
        child = parent;
      } else {
        if (typeof prototype === 'undefined') child = Object.create(Object.getPrototypeOf(parent));
        else child = Object.create(prototype);
      }

      if (circular) {
        const index = allParents.indexOf(parent);

        if (index !== -1) {
          return allChildren[index];
        }
        allParents.push(parent);
        allChildren.push(child);
      }

      for (const i in parent) {
        const propDescriptor = Object.getOwnPropertyDescriptor(parent, i);
        const hasGetter = ((typeof propDescriptor !== 'undefined') && (typeof propDescriptor.get !== 'undefined'));