当我为对象分配数字时，为什么TypeScript不会引发错误？

Question

I would expect an error on this code TypeScript :

var obj:Object;
var num:number;

obj = 4; // no error!
num = 4; // ok
num = obj; // error.

Any good reason for not getting an error?

Answer 1

Object : Provides functionality common to all JavaScript objects.

The Object object is contained in all other JavaScript objects; all of its methods and properties are available in all other objects. - Source

It works the way you described because a number is an Object , but an Object isn't necessarily a number .