使用 keyof 运算符获取打字稿类的属性类型 [英] Getting type of a property of a typescript class using keyof operator

问题描述

如 Typescript 文档中关于 keyof 运算符所述，可以使用下面的函数获取对象实例的属性.

As stated in the documentation of Typescript about the keyof operator, one can get a property of an object instance using the function below.

function getProperty<T, K extends keyof T>(o: T, name: K) {
    return o[name];
}

当然，可以通过将return o[name]替换为return typeof o[name]来获取属性的类型.有没有办法在不传递任何对象实例的情况下检索属性的类型?

Of course, one can get the type of the property by replacing return o[name] into return typeof o[name]. Is there a way to retrieve the type of the property without passing any object instance?

function getPropertyType<T>(name: keyof T) {
    // something like T[name]?
}

推荐答案

这是您要找的吗?

type PropType<TObj, TProp extends keyof TObj> = TObj[TProp];

并通过执行以下操作获取对象属性的类型:

and get type of an object property by doing:

type MyPropType = PropType<ObjType, '<key>'>;

和typescript中使用Pick的方式一样，如果传入了无效的key会报编译错误.

which is the same as the way of using Pick in typescript, and it can report compile error if there's any invalid key passed in.

更新

正如@astoilkov 所建议的，一个更简单的选择是 PropType['key'].

As @astoilkov suggested, a simpler alternative is PropType['key'].

这篇关于使用 keyof 运算符获取打字稿类的属性类型的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！