fix(fromEvent): Types now properly infer when resultSelector is provided (#6447)

* fix: fromEvent() type with resultSelector

* chore: api_guardian update

* test: improve the dtslint test on fromEvent()

* test: fix a typo in the dtslint test for fromEvent

Author: rocwang

api_guard/dist/types/index.d.ts

@@ -138,7 +138,7 @@ export declare function from<O extends ObservableInput<any>>(input: O, scheduler
 export declare function fromEvent<T>(target: HasEventTargetAddRemove<T> | ArrayLike<HasEventTargetAddRemove<T>>, eventName: string): Observable<T>;
 export declare function fromEvent<T, R>(target: HasEventTargetAddRemove<T> | ArrayLike<HasEventTargetAddRemove<T>>, eventName: string, resultSelector: (event: T) => R): Observable<R>;
 export declare function fromEvent<T>(target: HasEventTargetAddRemove<T> | ArrayLike<HasEventTargetAddRemove<T>>, eventName: string, options: EventListenerOptions): Observable<T>;
-export declare function fromEvent<T, R>(target: HasEventTargetAddRemove<T> | ArrayLike<HasEventTargetAddRemove<T>>, eventName: string, options: EventListenerOptions, resultSelector: (event: T) => R): Observable<T>;
+export declare function fromEvent<T, R>(target: HasEventTargetAddRemove<T> | ArrayLike<HasEventTargetAddRemove<T>>, eventName: string, options: EventListenerOptions, resultSelector: (event: T) => R): Observable<R>;
 export declare function fromEvent(target: NodeStyleEventEmitter | ArrayLike<NodeStyleEventEmitter>, eventName: string): Observable<unknown>;
 export declare function fromEvent<T>(target: NodeStyleEventEmitter | ArrayLike<NodeStyleEventEmitter>, eventName: string): Observable<T>;
 export declare function fromEvent<R>(target: NodeStyleEventEmitter | ArrayLike<NodeStyleEventEmitter>, eventName: string, resultSelector: (...args: any[]) => R): Observable<R>;

spec-dtslint/observables/fromEvent-spec.ts

@@ -18,6 +18,14 @@ it('should support an event target source result selector', () => {
   const a = fromEvent(eventTargetSource, "click", () => "clunk"); // $ExpectType Observable<string>
 });
 
+it('should support an event target source with options', () => {
+    const a = fromEvent(eventTargetSource, "click", { once: true }); // $ExpectType Observable<Event>
+});
+
+it('should support an event target source with options and result selector', () => {
+    const a = fromEvent(eventTargetSource, "click", { once: true }, () => "clunk"); // $ExpectType Observable<string>
+});
+
 declare const documentSource: HTMLDocument;
 
 it('should support a document source', () => {
@@ -29,6 +37,14 @@ it('should support a document source result selector', () => {
   const a = fromEvent(documentSource, "click", () => "clunk"); // $ExpectType Observable<string>
 });
 
+it('should support a document source with options', () => {
+    const a = fromEvent(documentSource, "click", { once: true }); // $ExpectType Observable<Event>
+});
+
+it('should support a document source with options and result selector', () => {
+    const a = fromEvent(documentSource, "click", { once: true }, () => "clunk"); // $ExpectType Observable<string>
+});
+
 // Pick the parts that will match NodeStyleEventEmitter. If this isn't done, it
 // will match JQueryStyleEventEmitter - because of the `on` and `off` methods -
 // despite the latter being declared last in the EventTargetLike union.

src/internal/observable/fromEvent.ts

@@ -76,7 +76,7 @@ export function fromEvent<T, R>(
   eventName: string,
   options: EventListenerOptions,
   resultSelector: (event: T) => R
-): Observable<T>;
+): Observable<R>;
 
 export function fromEvent(target: NodeStyleEventEmitter | ArrayLike<NodeStyleEventEmitter>, eventName: string): Observable<unknown>;
 /** @deprecated Do not specify explicit type parameters. Signatures with type parameters that cannot be inferred will be removed in v8. */