<script>
    //getType方法
    let getType = data => Object.prototype.toString.call(data);

    //测试数据
    let a,
        b = null,
        c = true,
        d = 10,
        e = '',
        f = {},
        g = [],
        h = new Date(),
        i = new RegExp('', 'gi'),
        j = function () {},
        k = Symbol(''),
        l = BigInt(0),
        m = class {};

    //输出
    console.log('a is', getType(a));//Undefined
    console.log('b is', getType(b));//Null
    console.log('c is', getType(c));//Boolean
    console.log('d is', getType(d));//Number
    console.log('e is', getType(e));//String
    console.log('f is', getType(f));//Object
    console.log('g is', getType(g));//Array
    console.log('h is', getType(h));//Date
    console.log('i is', getType(i));//RegExp
    console.log('j is', getType(j));//Function
    console.log('k is', getType(k));//Symbol
    console.log('l is', getType(l));//BigInt
    console.log('m is', getType(m));//Function，类是函数的语法糖，因此判断出来的是Function类型的数据
</script>