封装的一个判断数据类型的方法

~function (_){
  let types = "Array Object String Date Regexp Function Boolean Number Null Undefined".split(' ')
  function type() {
    return Object.prototype.toString.call(this).slice(8,-1)
  }
  for (let i=types.length; i--; i<0) {
    _['is'+ types[i]] = (function (ele){
      return function (elem) {
        console.log(elem)
        return type.call(elem) === ele
      }
    })(types[i])
  }
  return _
}(_={})
console.log(_)
console.log(_.isObject({})) // true