better wrapper for websocket

src/services/api/api.service.js

@@ -953,8 +953,52 @@ const MASTODON_STREAMING_EVENTS = new Set([
   'filters_changed'
 ])
 
+// A thin wrapper around WebSocket API that allows adding a pre-processor to it
+// Uses EventTarget and a CustomEvent to proxy events
+export const ProcessedWS = ({
+  url,
+  preprocessor = handleMastoWS,
+  id = 'Unknown'
+}) => {
+  const eventTarget = new EventTarget()
+  const socket = new WebSocket(url)
+  if (!socket) throw new Error(`Failed to create socket ${id}`)
+  const proxy = (original, eventName, processor = a => a) => {
+    original.addEventListener(eventName, (eventData) => {
+      eventTarget.dispatchEvent(new CustomEvent(
+        eventName,
+        { detail: processor(eventData) }
+      ))
+    })
+  }
+  socket.addEventListener('open', (wsEvent) => {
+    console.debug(`[WS][${id}] Socket connected`, wsEvent)
+  })
+  socket.addEventListener('error', (wsEvent) => {
+    console.debug(`[WS][${id}] Socket errored`, wsEvent)
+  })
+  socket.addEventListener('close', (wsEvent) => {
+    console.debug(
+      `[WS][${id}] Socket disconnected with code ${wsEvent.code}`,
+      wsEvent
+    )
+  })
+  socket.addEventListener('message', (wsEvent) => {
+    console.debug(
+      `[WS][${id}] Message received`,
+      wsEvent
+    )
+  })
+
+  proxy(socket, 'open')
+  proxy(socket, 'close')
+  proxy(socket, 'message', preprocessor)
+  proxy(socket, 'error')
+
+  return eventTarget
+}
+
 export const handleMastoWS = (wsEvent) => {
-  console.debug('Event', wsEvent)
   const { data } = wsEvent
   if (!data) return
   const parsedEvent = JSON.parse(data)