A minimal "null-modem" Firepad adapter

firepad-nulladapter.js

const {EntityManager, RichTextCodeMirror, EditorClient, FirebaseAdapter, utils,
       RichTextCodeMirrorAdapter} = Firepad.firepad;

var upstream = [];

class NullAdapter {
    constructor(userId, userColor) {
        this.userId_ = userId;
        this.color_ = userColor;
    }
    sendOperation(operation, callback) {
        console.log('operation', operation, callback);
        upstream.push({ a: this.userId_, o: operation.toJSON() });
        setTimeout(() => {
            this.trigger('ack');
            if (this.other)
                this.other.trigger('operation', operation);
        }, 0);
    }
    sendCursor(obj) {
        console.log('cursor', obj, this.userId_, this.color_);
        setTimeout(() => {
        if (this.other)
            this.other.trigger('cursor', this.userId_, obj, this.color_);
        });
    }

    registerCallbacks(callbacks) {
        for (var eventType in callbacks) {
            this.on(eventType, callbacks[eventType]);
        }
    }

}

utils.makeEventEmitter(NullAdapter, ['ready', 'cursor', 'operation', 'ack', 'retry']);


function createClient(cm, userId) {
    var entityManager_ = new EntityManager();

    var firebaseAdapter_ = new NullAdapter(userId, '#9999FF');
    var richTextCodeMirror_ = new RichTextCodeMirror(cm, entityManager_,
                                                     { cssPrefix: 'firepad-' }),
        editorAdapter_ = new RichTextCodeMirrorAdapter(richTextCodeMirror_);
    
    var client_ = new EditorClient(firebaseAdapter_, editorAdapter_);

    return client_;
}


$(() => {
    var div = $('<div>').appendTo('body');

    var cm1 = new CodeMirror(div[0], {lineNumbers: true});
        firepad1 = createClient(cm1, 'user1');
    
    var cm2 = new CodeMirror(div[0], {lineNumbers: true});
        firepad2 = createClient(cm2, 'user2');

    firepad1.serverAdapter.other = firepad2.serverAdapter;
    firepad2.serverAdapter.other = firepad1.serverAdapter;

    Object.assign(window, {cm1, cm2, firepad1, firepad2});  // for debugging
});