任意属性那个章节的运行效果和教程不同

https://ts.xcatliu.com/basics/type-of-object-interfaces.html interface Person { name: string; age?: number; } let tom: Person = { name: 'Tom', age: 25, gender: 'male' }; 我运行了，没有报错。ts 编译器版本：Version 4.5.5