链式获取数据

getValue.js

const getValue = (obj, keyChain = '', defaultValue = undefined) => {
  if (typeof keyChain !== 'string' || keyChain === '' || !obj)  return defaultValue || false;

  const check = (object, keyArr, hasNext = false) => {
    return ['[object Null]', '[object Undefined]'].indexOf(Object.prototype.toString.call(object[keyArr[0]])) === -1
      ? keyArr[1]
        ? check(object[keyArr[0]], keyArr.slice(1))
        : object[keyArr[0]]
      : hasNext ? undefined : defaultValue;
  };

  if (keyChain.indexOf('|') !== -1) {
    const queue = keyChain.split('|');
    const len = queue.length;
    for (let i = 0; i < len; i++) {
      const result = check(obj, queue[i].split('.'), i < len - 1);
      if (typeof result !== 'undefined' || i === len - 1) {
        return result;
      }
    }
  }

  return check(obj, keyChain.split('.'));
};