Emit cheatsheet: sending an event to all clients

The Emit cheatsheet page says that it's possible to send an event to all clients like this:

  // sending to all connected clients
  io.emit('an event sent to all connected clients');

However, according to this documentation page, io is an alias for io.sockets (source code; it seems this isn't mentioned in the server API documentation) which itself (according to this page and source code) is an alias for io.of('/') (assuming io is a Socket.IO server). I tested this, and io.emit(...) indeed behaves just like io.of('/').emit(...).

It seems that sending an event to all clients in all namespaces is not even possible (except if you manually send it to every namespace you're interested in with multiple io.of(...).emit(...) calls).

The following example from the cheatsheet is also likely wrong, but I haven't tested it:

  // sending to all clients on this node (when using multiple nodes)
  io.local.emit('hi', 'my lovely babies');

My guess is that it will send an event to every cilent on the default namespace of the current node (source code: it only sets a modifier on the default namespace).

Start with the Emit cheatsheet and compare its examples with the linked Default namespace and Server API pages. Check the cited locations in lib/index.ts to verify the namespace scope of io.emit and io.local. Done means the documentation accurately describes their scope and corrects any misleading examples.