自定义封装一个方法让这个方法可以判断所有的数据类型并返回

<script>
    function getType(obj) {
        let type = typeof obj;
        if (type !== "object") {
            return type;
        }
        if(Object.prototype.toString.call(obj).length === 13){
            return Object.prototype.toString.call(obj).slice(-5,-1);
        }
        if(Object.prototype.toString.call(obj).length === 14){
            return Object.prototype.toString.call(obj).slice(-6,-1);
        }
        return Object.prototype.toString.call(obj).slice(-7,-1);
    }
    console.log(getType(null));
    console.log(getType(1));
    console.log(getType('123'));
    console.log(getType(false));
    console.log(getType([1,2,3,4]));
    console.log(getType({a:123}));
    console.log(getType(null));
    console.log(getType(undefined));
    console.log(getType(()=>{}));
</script>