4.Object.prototype.toString.call()
![jq源码判断数据类型 jq源码判断数据类型](https://image.shishitao.com:8440/aHR0cHM6Ly9iYnNtYXguaWthZmFuLmNvbS9zdGF0aWMvTDNCeWIzaDVMMmgwZEhCekwyTnZiVzF2Ymk1amJtSnNiMmR6TG1OdmJTOXBiV0ZuWlhNdlkyOXdlV052WkdVdVoybG0uanBn.jpg?w=700)
1 var a = Object.prototype.toString;
2
3 console.log(a.call("aaa"));
4 console.log(a.call(1));
5 console.log(a.call(true));
6 console.log(a.call(null));
7 console.log(a.call(undefined));
8 console.log(a.call([]));
9 console.log(a.call(function() {}));
10 console.log(a.call({}));
![jq源码判断数据类型 jq源码判断数据类型](https://image.shishitao.com:8440/aHR0cHM6Ly9iYnNtYXguaWthZmFuLmNvbS9zdGF0aWMvTDNCeWIzaDVMMmgwZEhCekwyTnZiVzF2Ymk1amJtSnNiMmR6TG1OdmJTOXBiV0ZuWlhNdlkyOXdlV052WkdVdVoybG0uanBn.jpg?w=700)