How to reconnect to websocket after close connection [duplicate]

When the server closes the connection, the client does not try to reconnect. With some JS frameworks maybe, but the question was, at the time of this answer, tagged as plain Vanilla JS.

I'm a bit frustrated because the accepted, upvoted answer is plainly wrong, and it cost me some additional time while finding the correct solution.

Which is here: Reconnection of Client when server reboots in WebSocket

I found a great solution on this page: sam-low.com

Once the original connection has been closed, you need to create a new WebSocket object with new event listeners

function startWebsocket() {
  var ws = new WebSocket('ws://localhost:8080')

  ws.onmessage = function(e){
    console.log('websocket message event:', e)
  }

  ws.onclose = function(){
    // connection closed, discard old websocket and create a new one in 5s
    ws = null
    setTimeout(startWebsocket, 5000)
  }
}

startWebsocket();

Note that if there’s a problem reconnecting, the new WebSocket object will still receive another close event, meaning that onclose() will be executed even if it never technically opened. That’s why the delay of five seconds is sensible - without it you could find yourself creating and destroying thousands of websocket connections at a rate that would probably break something.