Consume changed plugins message in the UI

Summary: Relay message to the React app via postmessage. Later, we will subscribe to these messages and update the plugins

Reviewed By: lblasa

Differential Revision: D39539590

fbshipit-source-id: c6742e45330e71b63c135c0267e6e9c5817fc9ff

desktop/static/index.dev.html

@@ -68,6 +68,13 @@
         suppressErrors = true;
       });
 
+      socket.on('plugins-source-updated', (pluginsChanged) => {
+        window.postMessage({
+          type: 'plugins-source-updated',
+          data: pluginsChanged
+        })
+      })
+
       function openError(text) {
         if (suppressErrors) {
           return;

desktop/static/index.web.dev.html

@@ -65,13 +65,26 @@
       let suppressErrors = false;
 
       const socket = new WebSocket(`ws://${location.host}`);
+      window.devSocket = socket;
 
       socket.addEventListener('message', ({ data: dataRaw }) => {
         const message = JSON.parse(dataRaw.toString())
 
-        if (message.event === 'hasErrors') {
+        if (typeof message.event === 'string') {
+          switch (message.event) {
+            case 'hasErrors': {
               openError(message.payload);
               suppressErrors = true;
+              break;
+            }
+            case 'plugins-source-updated': {
+              window.postMessage({
+                type: 'plugins-source-updated',
+                data: message.payload
+              })
+              break;
+            }
+          }
         }
       })