1. /**
    2.  * 返回数据类型
    3.  *
    4.  * @return "null", "undefined",
    5.  * @return "Number", "String", "Boolean", "Symbol",
    6.  * @return "Array", "Object", "Function", "RegExp"
    7.  *
    8.  */
    9. let _toString = Object.prototype.toString;
    10. function toRawType (value) {
    11.   console.log("_toString.call(value)", _toString.call(value))
    12.   return _toString.call(value).slice(8, -1)
    13. }
    15. let configs = {
    16.   defNull: null,
    17.   defUndefined: undefined,
    18.   num: 20,
    19.   str: 'abcjsdkjdsjkfls',
    20.   bol: true,
    21.   arr: [1, 2],
    22.   sym: Symbol('hei'),
    23.   person: {
    24.     age: 18
    25.   },
    26.   fn: (_) => (_),
    27.   reg: /^Chapter [1-9][0-9]{0,1}/
    28. }
    30. for (let key in configs) {
    31.   let val = configs[key]
    32.   console.log(val, toRawType(val))
    33. }