Is there any way to pass the source from server to clients?

[common5]

I've read the docs and found that I can pass some info to server by adding options.source in submitOp(), but how can a client get source from server?
My code looks like:
`
// client.ts
doc.submitSource = true;
doc.on("op batch", async (op, source) => {
console.log(source);
}
// opSubmit.ts

doc.submitSource = true;
let op: { p: [string, number]; sd?: string; si?: string }[] = [];
op.push({ p: ["content", offset], si: insertPosition});
doc.submitOp(op, {source: userId}); // userId is defined as string type, and I'm pretty sure I've passed a not-empty string value to it
`
However, the source output in client.ts turns out to be false(a boolean value). Are there any possible solutions I may try to make the codes work as I've expected?

[alecgibson]

At the moment, submitSource will only send the source from a client to the server middleware (available on the x property). There's not currently any built-in way to send metadata about an op from the server to a client.

If you just want to pass the user ID around, we work our way around this by actively setting the id field for our Connection:

const SESSION_ID = randomUUID();
// connection ID should be unique, so if a user may have multiple sessions, you'll need to prefix
// with a session ID to keep it unique
connection.id = `${SESSION_ID}:${userId}`;

const doc = connection.get(...);

Then remotely you can check the src:

doc.on('op', (op, _source, id) => {
  const [sessionId, userId] = id.split(':');
});