Method extendDeep

lib/util.js:719–768

* Extend an object, and any object it contains. * * This does not replace deep objects, but dives into them * replacing individual elements instead. * * @method extendDeep * @param mergeInto {Object} The object to merge into * @param mergeFrom... {Object} - Any number of objects

(mergeInto, ...vargs)

   * @return {Object} The altered mergeInto object is returned
   */
  static extendDeep(mergeInto, ...vargs) {
    // Initialize
    let depth = vargs.pop();
    if (typeof (depth) != 'number') {
      vargs.push(depth);
      depth = DEFAULT_CLONE_DEPTH;
    }

    // Recursion detection
    if (depth < 0) {
      return mergeInto;
    }

    for (let mergeFrom of vargs) {
      // Cycle through each element of the object to merge from
      for (const prop in mergeFrom) {
        // save original value in deferred elements
        const fromIsDeferredFunc = mergeFrom[prop] instanceof DeferredConfig;
        const isDeferredFunc = mergeInto[prop] instanceof DeferredConfig;

        if (fromIsDeferredFunc && Object.hasOwnProperty.call(mergeInto, prop)) {
          mergeFrom[prop]._original = isDeferredFunc ? mergeInto[prop]._original : mergeInto[prop];
        }
        // Extend recursively if both elements are objects and target is not really a deferred function
        if (mergeFrom[prop] instanceof Date) {
          mergeInto[prop] = mergeFrom[prop];
        }

        if ((mergeFrom[prop] instanceof RegExp) ||
            (mergeFrom[prop] instanceof RawConfig)) {
          mergeInto[prop] = mergeFrom[prop];
        } else if (Util.isObject(mergeInto[prop]) && Util.isObject(mergeFrom[prop]) && !isDeferredFunc) {
          Util.extendDeep(mergeInto[prop], mergeFrom[prop], depth - 1);
        } else if (Util.isPromise(mergeFrom[prop])) {
          mergeInto[prop] = mergeFrom[prop];
        } else if (mergeFrom[prop] && typeof mergeFrom[prop] === 'object') {
          // Copy recursively if the mergeFrom element is an object (or array or fn)
          mergeInto[prop] = Util.cloneDeep(mergeFrom[prop], depth - 1);
        } else if (Object.getOwnPropertyDescriptor(Object(mergeFrom), prop)) {
          // Copy property descriptor otherwise, preserving accessors
          Object.defineProperty(mergeInto, prop, Object.getOwnPropertyDescriptor(Object(mergeFrom), prop));
        } else if (mergeInto[prop] !== mergeFrom[prop]) {
          mergeInto[prop] = mergeFrom[prop];
        }
      }
    }

    // Chain
    return mergeInto;
  }

  /**
   * Is the specified argument a regular javascript object?