Merge pull request #182 from hubert-deriv/fixing_keep_alive_example

Author: hubert-deriv

examples/keep_alive/index.js

@@ -5,7 +5,7 @@ const connection = new WebSocket(`wss://ws.binaryws.com/websockets/v3?app_id=${a
 
 const api = new DerivAPIBasic({ connection });
 
-const keepAlive = () => {
+const proposal = () => {
   api.subscribe({
     proposal: 1,
     subscribe: 1,
@@ -18,17 +18,21 @@ const keepAlive = () => {
     symbol: 'R_100',
     barrier: '+0.1',
   });
-  /*
-   * Send a ping ever 30 seconds to keep the connection alive, needs to use the same
-   * websocket connection as the one you want to maintain.
-   */
 };
 
-const keepAliveRes = async (res) => {
+// Send a ping every 30 seconds to keep the connection alive
+// Needs to use the same websocket connection as the one you want to maintain.
+const ping = () => {
+  setInterval(() => {
+    api.ping();
+  }, 30000);
+};
+
+const wsResponse = async (res) => {
   const data = JSON.parse(res.data);
   if (data.error !== undefined) {
     console.log('Error: %s ', data.error.message);
-    connection.removeEventListener('message', keepAliveRes, false);
+    connection.removeEventListener('message', wsResponse, false);
     await api.disconnect();
   } else if (data.msg_type === 'proposal') {
     console.log('Details: %s', data.proposal.longcode);
@@ -40,14 +44,15 @@ const keepAliveRes = async (res) => {
   }
 };
 
-const checkSignal = async () => {
-  await keepAlive();
-  connection.addEventListener('message', keepAliveRes);
+const checkSignal = () => {
+  proposal();
+  ping();
+  connection.addEventListener('message', wsResponse);
 };
 
 const endCall = () => {
-  connection.removeEventListener('message', keepAliveRes, false);
-  keepAlive().unsubscribe();
+  connection.removeEventListener('message', wsResponse, false);
+  proposal().unsubscribe();
 };
 
 const keep_alive_button = document.querySelector('#keep_alive');