How to implement delay with acknowledgements?

[shadypollen]

As per the documentation, we can have response-request using this:

// server-side
io.on("connection", (socket) => {
  socket.on("update item", (arg1, arg2, callback) => {
    console.log(arg1); // 1
    console.log(arg2); // { name: "updated" }
    callback({
      status: "ok"
    });
  });
});

// client-side
socket.emit("update item", "1", { name: "updated" }, (response) => {
  console.log(response.status); // ok
});

And also have a timeout function server-side using this:

const withTimeout = (onSuccess, onTimeout, timeout) => {
  let called = false;

  const timer = setTimeout(() => {
    if (called) return;
    called = true;
    onTimeout();
  }, timeout);

  return (...args) => {
    if (called) return;
    called = true;
    clearTimeout(timer);
    onSuccess.apply(this, args);
  }
}

socket.emit("hello", 1, 2, withTimeout(() => {
  console.log("success!");
}, () => {
  console.log("timeout!");
}, 1000));

However, to test that my timeout function works correctly I wanted to simulate a delayed response on the client-side. This doesn't work if I wrap the body of my response in a setTimeout. Is there a way to do this?

[darrachequesne]

I think the following shoud work:

// client-side
socket.on("hello", (arg1, arg2, callback) => {
  setTimeout(() => {
    callback("hi");
  }, 2000);
});

[shadypollen]

You're right! I had similar code but made a typo that I didn't notice until your comment made me look closer. Works like a charm now, thank you!