FEATURE: Save scroll position on bookmarks page (#15296)

Clicking on a bookmark and then back will preserve the scrolling
position.

app/assets/javascripts/discourse/app/components/bookmark-list.js

@@ -1,17 +1,53 @@
+import Component from "@ember/component";
+import { action } from "@ember/object";
+import { schedule } from "@ember/runloop";
+import bootbox from "bootbox";
+import discourseDebounce from "discourse-common/lib/debounce";
+import { openBookmarkModal } from "discourse/controllers/bookmark";
 import {
   openLinkInNewTab,
   shouldOpenInNewTab,
 } from "discourse/lib/click-track";
-import Component from "@ember/component";
+import Scrolling from "discourse/mixins/scrolling";
 import I18n from "I18n";
 import { Promise } from "rsvp";
-import { action } from "@ember/object";
-import bootbox from "bootbox";
-import { openBookmarkModal } from "discourse/controllers/bookmark";
 
-export default Component.extend({
+export default Component.extend(Scrolling, {
   classNames: ["bookmark-list-wrapper"],
 
+  didInsertElement() {
+    this._super(...arguments);
+    this.bindScrolling();
+    this.scrollToLastPosition();
+  },
+
+  willDestroyElement() {
+    this._super(...arguments);
+    this.unbindScrolling();
+  },
+
+  scrollToLastPosition() {
+    let scrollTo = this.session.bookmarkListScrollPosition;
+    if (scrollTo && scrollTo >= 0) {
+      schedule("afterRender", () => {
+        discourseDebounce(
+          this,
+          function () {
+            if (this.element && !this.isDestroying && !this.isDestroyed) {
+              window.scrollTo(0, scrollTo + 1);
+            }
+          },
+          0
+        );
+      });
+    }
+  },
+
+  scrolled() {
+    this._super(...arguments);
+    this.session.set("bookmarkListScrollPosition", window.scrollY);
+  },
+
   @action
   removeBookmark(bookmark) {
     return new Promise((resolve, reject) => {

app/assets/javascripts/discourse/app/controllers/user-activity-bookmarks.js

@@ -1,12 +1,12 @@
 import Controller, { inject as controller } from "@ember/controller";
+import EmberObject, { action, computed } from "@ember/object";
+import { equal, notEmpty } from "@ember/object/computed";
 import { iconHTML } from "discourse-common/lib/icon-library";
+import discourseComputed from "discourse-common/utils/decorators";
+import { ajax } from "discourse/lib/ajax";
 import Bookmark from "discourse/models/bookmark";
 import I18n from "I18n";
 import { Promise } from "rsvp";
-import EmberObject, { action, computed } from "@ember/object";
-import discourseComputed from "discourse-common/utils/decorators";
-import { equal, notEmpty } from "@ember/object/computed";
-import { ajax } from "discourse/lib/ajax";
 
 export default Controller.extend({
   queryParams: ["q"],
@@ -102,6 +102,7 @@ export default Controller.extend({
     if (response.bookmarks) {
       const bookmarkModels = response.bookmarks.map(this.transform);
       this.model.bookmarks.pushObjects(bookmarkModels);
+      this.session.set("bookmarksModel", this.model);
     }
   },
 

app/assets/javascripts/discourse/app/routes/user-activity-bookmarks.js

@@ -1,6 +1,7 @@
-import DiscourseRoute from "discourse/routes/discourse";
-import { ajax } from "discourse/lib/ajax";
 import { action } from "@ember/object";
+import { ajax } from "discourse/lib/ajax";
+import DiscourseRoute from "discourse/routes/discourse";
+import { Promise } from "rsvp";
 
 export default DiscourseRoute.extend({
   queryParams: {
@@ -8,9 +9,18 @@ export default DiscourseRoute.extend({
     q: { refreshModel: true },
   },
 
-  model(params) {
+  model(params, transition) {
     const controller = this.controllerFor("user-activity-bookmarks");
 
+    if (this.isPoppedState(transition) && this.session.bookmarksModel) {
+      return Promise.resolve(this.session.bookmarksModel);
+    }
+
+    this.session.setProperties({
+      bookmarksModel: null,
+      bookmarkListScrollPosition: null,
+    });
+
     return this._loadBookmarks(params)
       .then((response) => {
         if (!response.user_bookmark_list) {
@@ -22,7 +32,9 @@ export default DiscourseRoute.extend({
         );
         const loadMoreUrl = response.user_bookmark_list.more_bookmarks_url;
 
-        return { bookmarks, loadMoreUrl };
+        const model = { bookmarks, loadMoreUrl };
+        this.session.set("bookmarksModel", model);
+        return model;
       })
       .catch(() => controller.set("permissionDenied", true));
   },