deep recursive object comparison

gistfile1.txt

  /**
   * determine if existing elements for a given `root` || viewportDescriptor have the same observerOptions
   * We need to test this because two elements may be using the same `root` but have different observerOptions
   * i.e. viewportTolerance bottom: 500px vs. bottom: 0px
   * We only compare primitive types and objects; not arrays or functions
   *
   * @method _hasSimilarElement
   */
  _hasSimilarElement(observerOptions, elements) {
    return elements.some((testElement) => {
      return this._compareOptions(observerOptions, testElement.observerOptions);
    });
  }

  /**
   * @method _compareOptions
   */
  _compareOptions(observerOptions, elementOptions) {
    // simple comparison of string, number or even null/undefined
    let type1 = Object.prototype.toString.call(observerOptions);
    let type2 = Object.prototype.toString.call(elementOptions);
    if (type1 !== type2) {
      return false;
    } else if (type1 !== '[object Object]' && type2 !== '[object Object]') {
      return observerOptions === elementOptions;
    }

    // complex comparison for only type of [object Object]
    for (let key in observerOptions) {
      if (observerOptions.hasOwnProperty(key)) {
        // recursion to check nested
        if (this._compareOptions(observerOptions[key], elementOptions[key]) === false) {
          return false;
        }
      }
    }
    return true;
  }