Why different generics for Subscriber and Observable

[donaldpipowitch]

Not sure if this is a bug or not.

RxJS version:

5.0.0-rc.4

Code to reproduce:

rxjs/src/Observable.ts

Line 56 in e91d113

static create: Function = <T>(subscribe?: <R>(subscriber: Subscriber<R>) => TeardownLogic) => {

Expected behavior:

  static create: Function = <T>(subscribe?: <T>(subscriber: Subscriber<T>) => TeardownLogic) => {
    return new Observable<T>(subscribe);
  };

Actual behavior:

  static create: Function = <T>(subscribe?: <R>(subscriber: Subscriber<R>) => TeardownLogic) => {
    return new Observable<T>(subscribe);
  };

Additional information:

Maybe I misunderstood this part of RxJS, but I thought the Observable and Subscriber would share the same generic type here? Aren't the values I pass to subscriber.next from the same type I get when I use value$.map?

[kwonoj]

Actually I lost history in my memory for background of this - /cc @david-driscoll : any idea?

[david-driscoll]

that looks odd at first glance and probably needs to be changed.

that said since subject has a different create method than observable the typings mean nothing as it only has a function type.

[benlesh]

Looks incorrect to me.

[josh-sachs]

I came across this because I'm experiencing an issue where Typescript is not properly resolving the return type for Observable.create.

static create: Function = <T>(subscribe?: <T>(subscriber: Subscriber<T>) => TeardownLogic) => {
    return new Observable<T>(subscribe);
};

I think assigning create the global Function type is the issue. I believe this would resolve it...

static create = <T>(subscribe?: <T>(subscriber: Subscriber<T>) => TeardownLogic) => {
    return new Observable<T>(subscribe);
};

[lock]

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