"beforeReconnect" & "afterReconnect" callbacks

[bennycode]

We have a use case where we need to execute a function before every WebSocket reconnect. It would be great if the ReconnectingWebsocket instance could execute a function (like beforeReconnect) on every reconnect.

Another option, to fulfill our needs, would be making use of Promises for getUrl. But this requires the ReconnectingWebsocket to wait for a Promise to resolve.

Idea:

const getUrl = () => Promise.resolve('ws://echo.websocket.org/?id=something_special');
const rws = new ReconnectingWebSocket(getUrl);

[pladaria]

I like the idea of using a Promise for getUrl (as addition to other options like string or function)

[hhamalai]

I've been trying to implement async flow here too, however registering event listeners in this current manner gets complicated requiring the event handlers to be passed into ReconnectingWebSocket as parameters.

[pladaria]

Latest version supports passing () => Promise<string> as url parameter