Make ParameterDecorator and the like generic

lib Update Request

Missing / Incorrect Definition

ParameterDecorator is currently not generic, it can be attachted to any parameter. However, when a decorator is used for e.g. Dependency Injection purposes, some decorators require the type of the parameter to be consistent with the type of the decorator

Sample Code

E.g. we want this to work

class MyController {
  requestThings(@UserId() userId: number): Thing[] { return [] }
}

But this to fail:

class MyController {
  requestThings(@UserId() userId: string): Thing[] { return [] }
}

(as userId will be a number, not a string so the injection should ideally not be possible (at compile time)

Currently UserId is done more or less this way:

const UserId = (): ParameterDecorator => (target, key, index) => { 
  // do stuff
}

while I'd like to add number to ParameterDecorator:

const UserId = (): ParameterDecorator<number> => (target, key, index) => { 
  // do stuff
}

and I'd like typescript to check this when applying a decorator.

まず、ParameterDecorator の定義と、パラメーターデコレーターの適用に関するコンパイラーのチェックを見つけます。Issue の number と string の例を現在の動作と比較し、そのうえで、ジェネリックなパラメーター型をどのように表現し、検証すべきかを判断します。妥当なデコレーターの適用が受け入れられ、型が一致しないパラメーター型が適切なテストによって拒否されれば完了です。