SugarWs

export class SugarWs extends WebSocket {
  // implementation
}

So you can see that this websocket is not complicated extension of original browser’s (so and Deno’s) websocket.

Important improvements:

• .once() this method has the same API as the original .addEventListener() with only difference that it will auto-remove listener after first call
• .wait_for(state: 'open' | 'close') add more simple control over final states of websocket. So you can await for open or close and then do your stuff
  • important to note that this method only waiting for open or close states but not acting them
  • .wait_for('close').and_close() syntax sugar for:

    await sugar_ws.wait_for("close").and_close();
    // the same as
    sugar_ws.close();
    await sugar_ws.wait_for("close");

    • be careful:

      // this is not the same
      (await sugar_ws.wait_for("close")).close(); // <= should not work
      // also not work
      await sugar_ws.wait_for("close");
      sugar_ws.close();
      // last examples should not work because you started to wait
      // closing before "close" happen)))
      // and you blocked next line `.close()`
      // HOWEVER may be your simply waiting that `.close()` is happen somewhere
      // so in this situation it's ok to wait for this
      await sugar_ws.wait_for("close");

  • in any case be careful with usage of these methods especially in repeated scenarios… more tests are needed for this feature
• .send_if_open() will send only if websocket’s readyState is OPEN
• .on() alias for original’s .addEventListener()…so this is sugar only

Example of usage:

import { SugarWs } from "https://deno.land/x/sugar_ws/mod.ts";

const ws = await new SugarWs(`ws://localhost:3333`).wait_for("open");

ws.send_if_open("ping");
ws.once(
  "message",
  ({ data }) => console.log("may be FIRST but exactly LAST message:", data),
);

await new Promise<void>((resolve) => setTimeout(resolve, 1000));
await ws.wait_for("close").and_close();

ws.send_if_open("hi!"); // will not send because websocket is already closed

P.S.

Not enough tested the behavior for situations when .wait_for(...) promises started without resolving. For example start wait on open but websocket will never do it. In future the additional under-the-hood protections, may be options should be created to handle or auto-handle such situations.

see code