From da5e9af10a049570347a2279a3b3b11277f1afae Mon Sep 17 00:00:00 2001
From: Mark VanLandingham <mark.vanlandingham@discourse.org>
Date: Thu, 24 Oct 2019 09:27:03 -0500
Subject: [PATCH] FEATURE: Add remembering topic list for group pms (#8235)

* FEATURE: Add remembering topic list for group pms

* added findOrResetCachedBy helper in topic-list

* Created cached-topic-list.js

* Update app/assets/javascripts/discourse/routes/build-private-messages-route.js.es6

Co-Authored-By: Robin Ward <robin.ward@gmail.com>
---
 .../discourse/lib/cached-topic-list.js.es6       | 12 ++++++++++++
 .../routes/build-private-messages-route.js.es6   | 16 ++++------------
 .../user-private-messages-group-archive.js.es6   |  8 +++++---
 .../routes/user-private-messages-group.js.es6    |  8 +++++---
 4 files changed, 26 insertions(+), 18 deletions(-)
 create mode 100644 app/assets/javascripts/discourse/lib/cached-topic-list.js.es6

diff --git a/app/assets/javascripts/discourse/lib/cached-topic-list.js.es6 b/app/assets/javascripts/discourse/lib/cached-topic-list.js.es6
new file mode 100644
index 00000000000..78cd2c0c515
--- /dev/null
+++ b/app/assets/javascripts/discourse/lib/cached-topic-list.js.es6
@@ -0,0 +1,12 @@
+export function findOrResetCachedTopicList(session, filter) {
+  const lastTopicList = session.get("topicList");
+  if (lastTopicList && lastTopicList.filter === filter) {
+    return lastTopicList;
+  } else {
+    session.setProperties({
+      topicList: null,
+      topicListScrollPosition: null
+    });
+    return false;
+  }
+}
diff --git a/app/assets/javascripts/discourse/routes/build-private-messages-route.js.es6 b/app/assets/javascripts/discourse/routes/build-private-messages-route.js.es6
index 820a41cf8d7..751e8f8fd2a 100644
--- a/app/assets/javascripts/discourse/routes/build-private-messages-route.js.es6
+++ b/app/assets/javascripts/discourse/routes/build-private-messages-route.js.es6
@@ -1,4 +1,5 @@
 import UserTopicListRoute from "discourse/routes/user-topic-list";
+import { findOrResetCachedTopicList } from "discourse/lib/cached-topic-list";
 
 // A helper to build a user topic list route
 export default (viewName, path, channel) => {
@@ -18,19 +19,10 @@ export default (viewName, path, channel) => {
     },
 
     model() {
-      const session = Discourse.Session.current();
-      let filter =
+      const filter =
         "topics/" + path + "/" + this.modelFor("user").get("username_lower");
-      let lastTopicList = session.get("topicList");
-      if (lastTopicList && lastTopicList.filter === filter) {
-        return lastTopicList;
-      } else {
-        session.setProperties({
-          topicList: null,
-          topicListScrollPosition: null
-        });
-        return this.store.findFiltered("topicList", { filter });
-      }
+      const lastTopicList = findOrResetCachedTopicList(this.session, filter);
+      return lastTopicList ? lastTopicList : this.store.findFiltered("topicList", { filter });
     },
 
     setupController() {
diff --git a/app/assets/javascripts/discourse/routes/user-private-messages-group-archive.js.es6 b/app/assets/javascripts/discourse/routes/user-private-messages-group-archive.js.es6
index 0d37dac9235..b8ae1b05816 100644
--- a/app/assets/javascripts/discourse/routes/user-private-messages-group-archive.js.es6
+++ b/app/assets/javascripts/discourse/routes/user-private-messages-group-archive.js.es6
@@ -1,4 +1,5 @@
 import createPMRoute from "discourse/routes/build-private-messages-route";
+import { findOrResetCachedTopicList } from "discourse/lib/cached-topic-list";
 
 export default createPMRoute("groups", "private-messages-groups").extend({
   groupName: null,
@@ -16,9 +17,10 @@ export default createPMRoute("groups", "private-messages-groups").extend({
 
   model(params) {
     const username = this.modelFor("user").get("username_lower");
-    return this.store.findFiltered("topicList", {
-      filter: `topics/private-messages-group/${username}/${params.name}/archive`
-    });
+    const filter =
+      `topics/private-messages-group/${username}/${params.name}/archive`;
+    const lastTopicList = findOrResetCachedTopicList(this.session, filter);
+    return lastTopicList ? lastTopicList : this.store.findFiltered("topicList", { filter });
   },
 
   afterModel(model) {
diff --git a/app/assets/javascripts/discourse/routes/user-private-messages-group.js.es6 b/app/assets/javascripts/discourse/routes/user-private-messages-group.js.es6
index cea1b022f41..5cb253c3b16 100644
--- a/app/assets/javascripts/discourse/routes/user-private-messages-group.js.es6
+++ b/app/assets/javascripts/discourse/routes/user-private-messages-group.js.es6
@@ -1,4 +1,5 @@
 import createPMRoute from "discourse/routes/build-private-messages-route";
+import { findOrResetCachedTopicList } from "discourse/lib/cached-topic-list";
 
 export default createPMRoute("groups", "private-messages-groups").extend({
   groupName: null,
@@ -11,9 +12,10 @@ export default createPMRoute("groups", "private-messages-groups").extend({
 
   model(params) {
     const username = this.modelFor("user").get("username_lower");
-    return this.store.findFiltered("topicList", {
-      filter: `topics/private-messages-group/${username}/${params.name}`
-    });
+    const filter =
+      `topics/private-messages-group/${username}/${params.name}`;
+    const lastTopicList = findOrResetCachedTopicList(this.session, filter);
+    return lastTopicList ? lastTopicList : this.store.findFiltered("topicList", { filter });
   },
 
   afterModel(model) {