[Glitch] Fix public timelines being broken by new toots when they are not mounted

Port be1c634b2b to glitch-soc

app/javascript/flavours/glitch/actions/compose.js

@@ -175,7 +175,9 @@ export function submitCompose(routerHistory) {
       // To make the app more responsive, immediately get the status into the columns
 
       const insertIfOnline = (timelineId) => {
-        if (getState().getIn(['timelines', timelineId, 'items', 0]) !== null) {
+        const timeline = getState().getIn(['timelines', timelineId]);
+
+        if (timeline && timeline.get('items').size > 0 && timeline.getIn(['items', 0]) !== null && timeline.get('online')) {
           dispatch(updateTimeline(timelineId, { ...response.data }));
         }
       };

app/javascript/flavours/glitch/actions/streaming.js

@@ -3,6 +3,7 @@ import {
   updateTimeline,
   deleteFromTimelines,
   expandHomeTimeline,
+  connectTimeline,
   disconnectTimeline,
 } from './timelines';
 import { updateNotifications, expandNotifications } from './notifications';
@@ -15,7 +16,12 @@ export function connectTimelineStream (timelineId, path, pollingRefresh = null,
 
   return connectStream (path, pollingRefresh, (dispatch, getState) => {
     const locale = getState().getIn(['meta', 'locale']);
+
     return {
+      onConnect() {
+        dispatch(connectTimeline(timelineId));
+      },
+
       onDisconnect() {
         dispatch(disconnectTimeline(timelineId));
       },

app/javascript/flavours/glitch/actions/timelines.js

@@ -12,6 +12,7 @@ export const TIMELINE_EXPAND_FAIL    = 'TIMELINE_EXPAND_FAIL';
 
 export const TIMELINE_SCROLL_TOP = 'TIMELINE_SCROLL_TOP';
 
+export const TIMELINE_CONNECT    = 'TIMELINE_CONNECT';
 export const TIMELINE_DISCONNECT = 'TIMELINE_DISCONNECT';
 
 export function updateTimeline(timeline, status, accept) {
@@ -145,6 +146,13 @@ export function scrollTopTimeline(timeline, top) {
   };
 };
 
+export function connectTimeline(timeline) {
+  return {
+    type: TIMELINE_CONNECT,
+    timeline,
+  };
+};
+
 export function disconnectTimeline(timeline) {
   return {
     type: TIMELINE_DISCONNECT,