fix(state channels): wait for connection to be established before sending generic message (#723)

* feat(state channels): add .off method

* fix(state channels): wait for connection to be established before sending generic message

Author: mpowaga

es/channel/index.js

@@ -65,6 +65,16 @@ function on (event, callback) {
   eventEmitters.get(this).on(event, callback)
 }
 
+/**
+ * Remove event listener function
+ *
+ * @param {String} event - Event name
+ * @param {Function} callback - Callback function
+ */
+function off (event, callback) {
+  eventEmitters.get(this).removeListener(event, callback)
+}
+
 /**
  * Close the connection
  */
@@ -659,7 +669,24 @@ function sendMessage (message, recipient) {
   if (typeof message === 'object') {
     info = JSON.stringify(message)
   }
-  send(this, { jsonrpc: '2.0', method: 'channels.message', params: { info, to: recipient } })
+  const doSend = (channel) => send(channel, {
+    jsonrpc: '2.0',
+    method: 'channels.message',
+    params: { info, to: recipient }
+  })
+  if (this.status() === 'connecting') {
+    const onStatusChanged = (status) => {
+      if (status !== 'connecting') {
+        // For some reason we can't immediately send a message when connection is
+        // established established. Thus we wait 500ms which seems to work.
+        setTimeout(() => doSend(this), 500)
+        this.off('statusChanged', onStatusChanged)
+      }
+    }
+    this.on('statusChanged', onStatusChanged)
+  } else {
+    doSend(this)
+  }
 }
 
 async function reconnect (options, txParams) {
@@ -724,6 +751,7 @@ const Channel = AsyncInit.compose({
   },
   methods: {
     on,
+    off,
     status,
     state,
     id,

es/channel/internal.js

@@ -225,6 +225,7 @@ async function initialize (channel, channelOptions) {
   eventEmitters.set(channel, new EventEmitter())
   sequence.set(channel, 0)
   rpcCallbacks.set(channel, new Map())
+  changeStatus(channel, 'connecting')
   const ws = await WebSocket(wsUrl, {
     onopen: () => {
       changeStatus(channel, 'connected')