判空函数

const isEmpty = (value) => {
  let tmp = value;
  if (value === null || value === undefined) {
    tmp = '';

    // true/false will be translated to "ture"/"false", so, boolean type always not empty
  } else if (typeof value === 'number' || typeof value === 'boolean') {
    tmp = String(value);
  }

  let ret = tmp;
  if (typeof tmp === 'string' || Array.isArray(tmp)) {
    ret = tmp.length;
  } else if (typeof tmp === 'object') {
    ret = Object.keys(tmp).length;
  }

  return !ret;
};