refactor(router): create pipeable afterPreactivation function (#25740)

PR Close #25740

packages/router/src/operators/after_preactivation.ts

@@ -0,0 +1,29 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {MonoTypeOperatorFunction} from 'rxjs';
+import {map, mergeMap} from 'rxjs/operators';
+
+import {RouterHook} from '../router';
+import {RouterStateSnapshot} from '../router_state';
+import {UrlTree} from '../url_tree';
+
+export function afterPreactivation(
+    hook: RouterHook, navigationId: number, appliedUrlTree: UrlTree, rawUrlTree: UrlTree,
+    skipLocationChange: boolean, replaceUrl: boolean):
+    MonoTypeOperatorFunction<{appliedUrl: UrlTree, snapshot: RouterStateSnapshot}> {
+  return function(source) {
+    return source.pipe(mergeMap(
+        p => hook(
+                 p.snapshot,
+                 {
+                     navigationId, appliedUrlTree, rawUrlTree, skipLocationChange, replaceUrl,
+                 })
+                 .pipe(map(() => p))));
+  };
+}

packages/router/src/router.ts

@@ -31,6 +31,7 @@ import {DefaultUrlHandlingStrategy, UrlHandlingStrategy} from './url_handling_st
 import {UrlSerializer, UrlTree, containsTree, createEmptyUrlTree} from './url_tree';
 import {forEach} from './utils/collection';
 import {TreeNode, nodeChildrenAsMap} from './utils/tree';
+import { afterPreactivation } from './operators/after_preactivation';
 
 
 
@@ -777,17 +778,13 @@ export class Router {
             of (p)
       ));
 
-      const preactivationDone$ =
-          preactivationResolveData$.pipe(mergeMap((p): Observable<NavStreamValue> => {
-            if (typeof p === 'boolean' || this.navigationId !== id) return of (false);
-            return this.hooks
-                .afterPreactivation(p.snapshot, {
-                  navigationId: id,
-                  appliedUrlTree: url,
-                  rawUrlTree: rawUrl, skipLocationChange, replaceUrl,
-                })
-                .pipe(map(() => p));
-          }));
+      const preactivationDone$: Observable<NavStreamValue> =
+          preactivationResolveData$.pipe(mergeMap(p =>
+            typeof p === 'boolean' || this.navigationId !== id ? of (false) :
+            of (p).pipe(
+              afterPreactivation(this.hooks.afterPreactivation, id, url, rawUrl, skipLocationChange, replaceUrl),
+              map(() => p))
+            ));
 
 
       // create router state