Update JavaScript example on https://docs.bitfinex.com/reference/ws-public-ticker

[manoelcampos]

Issue type

• bug
• missing functionality
• performance
• feature request
• Example / Documentation

Brief description

The JS example available at the documentation site is designed to work with Node.js. However, if we make some little changes, it will also work out-of-the-box on the browser after we remove the require line:

-    const ws = require('ws')
+    const WebSocket = require('ws')

-    const w = new ws('wss://api-pub.bitfinex.com/ws/2')
+    const ws = new WebSocket('wss://api-pub.bitfinex.com/ws/2')
 
-    w.on('message', (msg) => console.log(msg))
+    ws.onmessage = (msg) => console.log(msg)
 
-    let msg = JSON.stringify({ 
+    const msg = JSON.stringify({ 
         event: 'subscribe', 
         channel: 'ticker', 
         symbol: 'tBTCUSD' 
     })
 
-    w.on('open', () => w.send(msg))
+    ws.onopen = () => ws.send(msg)

Additional Notes:

I couldn't find the mentioned documentation site here at GitHub, so that I could send a PR proposing the changes.