mergeExclude(obj1, obj2 = {}, exclude = []) {
    for (let key in obj2) {
      if (exclude.indexOf(key) < 0 && obj2[key] !== undefined) obj1[key] = obj2[key];
    }
    return obj1;
  }
Merge one object into another object (not including the key to be removed)
@param {object} obj1 - target object
@param {object} obj2 - source object
@return {object} result object
@public