refactor(core): use stream in rxResource instead of loader (angular#59910)

With the changes in angular#59573, `resource` can now define a `stream` rather than a `loader`.
In the same PR, `rxResource` was updated to leverage this new functionality to handle multiple responses from the underlying observable,
rather than just the first one as it was previously.
This commit renames the `loader` option of `rxResource` into `stream` to be better aligned with its new behavior.

The previous version is temporarily kept and marked as deprecated to help migrating the current usage.

Before
```
usersResource = rxResource({
  request: () => ...,
  loader: ({ request }) => ...
});
```

After
```
usersResource = rxResource({
  request: () => ...,
  stream: ({ request }) => ...
});
```

PR Close angular#59910

Author: cexbrayat

goldens/public-api/core/rxjs-interop/index.api.md

@@ -26,10 +26,7 @@ export function rxResource<T, R>(opts: RxResourceOptions<T, R> & {
 export function rxResource<T, R>(opts: RxResourceOptions<T, R>): ResourceRef<T | undefined>;
 
 // @public
-export interface RxResourceOptions<T, R> extends BaseResourceOptions<T, R> {
-    // (undocumented)
-    loader: (params: ResourceLoaderParams<R>) => Observable<T>;
-}
+export type RxResourceOptions<T, R> = RxResourceStreamOptions<T, R> | RxResourceLoaderOptions<T, R>;
 
 // @public
 export function takeUntilDestroyed<T>(destroyRef?: DestroyRef): MonoTypeOperatorFunction<T>;

packages/core/rxjs-interop/src/rx_resource.ts

@@ -17,17 +17,35 @@ import {
 } from '../../src/core';
 import {Observable, Subscription} from 'rxjs';
 
+/**
+ * Like `ResourceOptions` but uses an RxJS-based `stream`.
+ *
+ * @experimental
+ */
+interface RxResourceStreamOptions<T, R> extends BaseResourceOptions<T, R> {
+  stream: (params: ResourceLoaderParams<R>) => Observable<T>;
+}
+
 /**
  * Like `ResourceOptions` but uses an RxJS-based `loader`.
  *
  * @experimental
+ * @deprecated Use `stream` instead of `loader`.
  */
-export interface RxResourceOptions<T, R> extends BaseResourceOptions<T, R> {
+interface RxResourceLoaderOptions<T, R> extends BaseResourceOptions<T, R> {
+  /** @deprecated Use `stream` instead of `loader`. */
   loader: (params: ResourceLoaderParams<R>) => Observable<T>;
 }
 
 /**
- * Like `resource` but uses an RxJS based `loader` which maps the request to an `Observable` of the
+ * Like `ResourceOptions` but uses an RxJS-based `stream`.
+ *
+ * @experimental
+ */
+export type RxResourceOptions<T, R> = RxResourceStreamOptions<T, R> | RxResourceLoaderOptions<T, R>;
+
+/**
+ * Like `resource` but uses an RxJS based `stream` which maps the request to an `Observable` of the
  * resource's value.
  *
  * @experimental
@@ -37,7 +55,7 @@ export function rxResource<T, R>(
 ): ResourceRef<T>;
 
 /**
- * Like `resource` but uses an RxJS based `loader` which maps the request to an `Observable` of the
+ * Like `resource` but uses an RxJS based `stream` which maps the request to an `Observable` of the
  * resource's value.
  *
  * @experimental
@@ -67,7 +85,11 @@ export function rxResource<T, R>(opts: RxResourceOptions<T, R>): ResourceRef<T |
         resolve = undefined;
       }
 
-      sub = opts.loader(params).subscribe({
+      // loader is kept for backwards compatibility
+      const streamOrLoader =
+        (opts as RxResourceStreamOptions<T, R>).stream ??
+        (opts as RxResourceLoaderOptions<T, R>).loader;
+      sub = streamOrLoader(params).subscribe({
         next: (value) => send({value}),
         error: (error) => send({error}),
         complete: () => {

packages/core/rxjs-interop/test/rx_resource_spec.ts

@@ -16,7 +16,7 @@ describe('rxResource()', () => {
     const injector = TestBed.inject(Injector);
     const appRef = TestBed.inject(ApplicationRef);
     const res = rxResource({
-      loader: () => of(1),
+      stream: () => of(1),
       injector,
     });
     await appRef.whenStable();
@@ -31,7 +31,7 @@ describe('rxResource()', () => {
     let lastSeenRequest: number = 0;
     rxResource({
       request,
-      loader: ({request}) => {
+      stream: ({request}) => {
         lastSeenRequest = request;
         return new Observable((sub) => {
           if (request === 2) {
@@ -61,7 +61,7 @@ describe('rxResource()', () => {
     const appRef = TestBed.inject(ApplicationRef);
     const response = new BehaviorSubject(1);
     const res = rxResource({
-      loader: () => response,
+      stream: () => response,
       injector,
     });
     await appRef.whenStable();