如何在TypeScript类成员函数中使用筛选后的keyof this

下面是我想要做的一些代码:

1. 具有几个成员字段和函数的类；
2. 这个类提供一个名为callMe的函数；
3. callMe的参数将被限制为此类的成员名称之一；
4. 只接受成员字段的名称，应排除成员函数的名称.

奇怪的是:

1. 如果我用一个实例调用callMe函数，一切都会像预期的那样顺利.
2. 但是，如果我在这个类的成员函数中调用callMe，就会出现错误.

详情如下:

// I'd like to use this `Filter` to get all the non-function field names of a type
type Filter<T> = { [K in keyof T]: T[K] extends Function ? never : K }[keyof T] & string;

class BaseClass {
  // This function should only accept a parameter which only matches the non-function member names
  public callMe<V extends Filter<this>>(param: V) {}
}

class MyClass extends BaseClass {
  // These member field should be involved
  public stringField: string = '';
  public numberField: number = 0;
  public booleanField: boolean = false;
  // These member functions should be excluded
  public shouldBeExclude() {}
  public test() {
    // this line is error:
    // TS2345: Argument of type string is not assignable to parameter of type Filter<this>
    // Type 'string' is not assignable to type 'this[keyof this] extends Function ? never : keyof this'
    this.callMe('stringField');
  }
}

const instance = new MyClass();
// However these lines work as expected
instance.callMe('stringField'); // Valid
instance.callMe('numberField'); // Valid
instance.callMe('shouldBeExclude'); // Invalid: TS2345: Argument of type 'shouldBeExclude' is not assignable to parameter of type Filter<MyClass>

Playground个

我怎样才能使Filter与成员函数test一起工作？