import { isDef, isObject } from '.';

function assignKey(to, from, key) {
  var val = from[key];

  if (!isDef(val)) {
    return;
  }

  if (!Object.prototype.hasOwnProperty.call(to, key) || !isObject(val)) {
    to[key] = val;
  } else {
    // eslint-disable-next-line no-use-before-define
    to[key] = deepAssign(Object(to[key]), from[key]);
  }
}

export function deepAssign(to, from) {
  Object.keys(from).forEach(function (key) {
    assignKey(to, from, key);
  });
  return to;
}
export function deepClone(obj) {
  if (Array.isArray(obj)) {
    return obj.map(function (item) {
      return deepClone(item);
    });
  }

  if (typeof obj === 'object') {
    return deepAssign({}, obj);
  }

  return obj;
}