chore: address comments

spec-dtslint/Notification-spec.ts

@@ -1,4 +1,4 @@
-import { Notification } from "../dist/types/internal/Notification";
+import { Notification } from 'rxjs';
 
 describe('Notification', () => {
   // Basic method tests

src/internal/Notification.ts

@@ -193,7 +193,7 @@ export class Notification<T> {
     throw new Error('unexpected notification kind value');
   }
 
-  private static completeNotification: Notification<never> & CompleteNotification = new Notification('C') as any;
+  private static completeNotification = new Notification('C') as Notification<never> & CompleteNotification;
   /**
    * A shortcut to create a Notification instance of the type `next` from a
    * given value.
@@ -205,8 +205,8 @@ export class Notification<T> {
    * and use them. Rather, try to create POJOs matching the signature outlined in {@link ObservableNotification}.
    * For example: `{ kind: 'N', value: 1 }`, `{kind: 'E', error: new Error('bad') }`, or `{ kind: 'C' }`.
    */
-  static createNext<T>(value: T): Notification<T> & NextNotification<T> {
-    return new Notification('N', value) as any;
+  static createNext<T>(value: T) {
+    return new Notification('N', value) as Notification<T> & NextNotification<T>;
   }
 
   /**
@@ -220,8 +220,8 @@ export class Notification<T> {
    * and use them. Rather, try to create POJOs matching the signature outlined in {@link ObservableNotification}.
    * For example: `{ kind: 'N', value: 1 }`, `{kind: 'E', error: new Error('bad') }`, or `{ kind: 'C' }`.
    */
-  static createError(err?: any): Notification<never> & ErrorNotification {
-    return new Notification('E', undefined, err) as any;
+  static createError(err?: any) {
+    return new Notification('E', undefined, err) as Notification<never> & ErrorNotification;
   }
 
   /**
@@ -266,7 +266,7 @@ export function observeNotification<T>(notification: ObservableNotification<T>,
  * same "shape" as other notifications in v8.
  * @internal
  */
-export const COMPLETE_NOTIFICATION = (() => createNotification('C', undefined, undefined))();
+export const COMPLETE_NOTIFICATION = (() => createNotification('C', undefined, undefined) as CompleteNotification)();
 
 /**
  * Internal use only. Creates an optimized error notification that is the same "shape"
@@ -282,8 +282,8 @@ export function errorNotification(error: any): ErrorNotification {
  * as other notifications.
  * @internal
  */
-export function nextNotification<T>(value: T): NextNotification<T> {
-  return createNotification('N', value, undefined) as any;
+export function nextNotification<T>(value: T) {
+  return createNotification('N', value, undefined) as NextNotification<T>;
 }
 
 /**
@@ -292,10 +292,10 @@ export function nextNotification<T>(value: T): NextNotification<T> {
  * TODO: This is only exported to support a crazy legacy test in `groupBy`.
  * @internal
  */
-export function createNotification(kind: 'N'|'E'|'C', value: any, error: any) {
+export function createNotification(kind: 'N' | 'E' | 'C', value: any, error: any) {
   return {
     kind,
     value,
-    error
+    error,
   };
-}
+}

src/internal/operators/dematerialize.ts

@@ -2,7 +2,7 @@ import { Operator } from '../Operator';
 import { Observable } from '../Observable';
 import { Subscriber } from '../Subscriber';
 import { observeNotification } from '../Notification';
-import { OperatorFunction, ObservableNotification, NextNotification } from '../types';
+import { OperatorFunction, ObservableNotification, ValueFromNotification } from '../types';
 
 /**
  * Converts an Observable of {@link ObservableNotification} objects into the emissions
@@ -51,13 +51,13 @@ import { OperatorFunction, ObservableNotification, NextNotification } from '../t
  * @return {Observable} An Observable that emits items and notifications
  * embedded in Notification objects emitted by the source Observable.
  */
-export function dematerialize<N extends ObservableNotification<any>>(): OperatorFunction<N, GetNotificationValueOf<N>> {
+export function dematerialize<N extends ObservableNotification<any>>(): OperatorFunction<N, ValueFromNotification<N>> {
   return function dematerializeOperatorFunction(source: Observable<N>) {
     return source.lift(new DeMaterializeOperator<N>());
   };
 }
 
-class DeMaterializeOperator<N extends ObservableNotification<any>> implements Operator<N, GetNotificationValueOf<N>> {
+class DeMaterializeOperator<N extends ObservableNotification<any>> implements Operator<N, ValueFromNotification<N>> {
   call(subscriber: Subscriber<any>, source: any): any {
     return source.subscribe(new DeMaterializeSubscriber<N>(subscriber));
   }
@@ -69,17 +69,11 @@ class DeMaterializeOperator<N extends ObservableNotification<any>> implements Op
  * @extends {Ignored}
  */
 class DeMaterializeSubscriber<N extends ObservableNotification<any>> extends Subscriber<N> {
-  constructor(destination: Subscriber<GetNotificationValueOf<N>>) {
+  constructor(destination: Subscriber<ValueFromNotification<N>>) {
     super(destination);
   }
 
   protected _next(notification: N) {
     observeNotification(notification, this.destination);
   }
 }
-
-type GetNotificationValueOf<T> = T extends { kind: 'N'|'E'|'C' } ?
-  (T extends NextNotification<any> ?
-    (T extends { value: infer V } ? V : undefined )
-  : never)
-  : never;

src/internal/types.ts

@@ -237,4 +237,13 @@ export type Tail<X extends any[]> =
  * If you have `T extends Array<any>`, and pass a `string[]` to it,
  * `ValueFromArray<T>` will return the actual type of `string`.
  */
-export type ValueFromArray<A> = A extends Array<infer T> ? T : never;
+export type ValueFromArray<A> = A extends Array<infer T> ? T : never;
+
+/**
+ * Gets the value type from an {@link ObservableNotification}, if possible.
+ */
+export type ValueFromNotification<T> = T extends { kind: 'N'|'E'|'C' } ?
+  (T extends NextNotification<any> ?
+    (T extends { value: infer V } ? V : undefined )
+  : never)
+  : never;