How to wait for a WebSocket's readyState to change

Question

I\'m trying to implement a WebSocket with a fallback to polling. If the WebSocket connection succeeds, readyState becomes 1, but if it fails, readyState

Answer 1

I am not using pooling at all. Instead, I use queuing. First I create new send function and a queue:

var msgs = []
function send (msg) {
  if (ws.readyState !== 1) {
    msgs.push(msg)
  } else {
    ws.send(msg)
  }
}

Then I need to read and send when the connection is first established:

function my_element_click () {
  if (ws == null){
    ws = new WebSocket(websocket_url)
    ws.onopen = function () {
      while (msgs.length > 0) {
        ws.send(msgs.pop())
      }
    }
    ws.onerror = function(error) {
      // do sth on error
    }
  } 
  msg = {type: 'mymessage', data: my_element.value}
  send(JSON.stringify(msg))
}

WebSocket connection in this example is created only on the first click. Usually, on second messages start to be sent directly.