I have a question regarding the .listen method for coloseus.js client.

So, the thing is, that I send the current position & rotation to the server, which looks something like this:

serverRoom.send({
    action: 'entity:transform:update',
    detail: {
        id: mesh.id,
        transformMatrix: [
            meshTransform.position.x,
            meshTransform.position.y,
            meshTransform.position.z,
            meshTransform.rotation.x,
            meshTransform.rotation.y,
            meshTransform.rotation.z,
            meshTransform.rotation.w,
        ],
    },
});

my room's state looks something like this:

public onInit (options) {
    this.setState({
        entities: {}, // key_id: { id: 1, transformMatrix: [0,0,0,0,0,0,0] }
    });
}

Now, I want to listen for changes of other entities like that:

serverRoom.listen('entities/:id/transformMatrix', (change: DataChange) => {
// listen for changes
});

But that doesn't seem to work (it only fires for the first add operation & the remove operation; It doesn't ever fire the replace operation), if the transformMatrix variable is an array. My temporary workaround is, to set it to a string, and also send the transformMatrix as a string.

Is there a way I could get the array inside the serverRoom.listen() method?

This section needs more documentation and examples indeed.

You won't receive "replace" operations on "entities/:id/transformMatrix" this way because the listen() checks for the exact location of the variable, and it won't go deeper.

You can listen to arrays like this:

serverRoom.listen("entities/:id/transformMatrix/:index", (change: DataChange) => {
  console.log(change.path.index + " is now " + change.value);
});

Hope this helps! Cheers!