Mutate document without side effect

1

Hi, I’m attaching collaborative editing library to ProseMirror, and the following problems arise.

  1. Client A edit the document, and broadcast edited range to other client.
  • The broadcast function is called from plugin.state.apply
  1. Client B receives changes and applies them to documents.
  • plugin.state.apply called again when apply changes.
  1. Client A receives changes and applies them to documents… and step 2-3 repeat forever.

Is there any way to change the contents of the document without side effects? or Am I using something wrong? (I think I am, but I don’t know what it is)

The code of my plugin is like this.

{
  state: {
    apply(tr) {
      if (tr.docChanged) {
        broadcastChanges(foo(tr));
      }
    }
  },
  view(view) {
    collabDocument.onChange((change) => {
      if (client.id === change.user.id) {
        return;
      }
      let { state } = view;
      state = state.apply(state.tr.insertText(change.text, changes.from));
      view.updateState(state);
    });
  },
}
2

I would check how prosemirror-collab does it. prosemirror-collab/collab.js at master · ProseMirror/prosemirror-collab · GitHub

3

You can use transaction.setMeta and transaction.getMeta to keep track of whats caused by the current user and should be broadcasted and what is coming in and shouldn’t be broadcasted again.