The console.log statements in helloworld.js will be output in electron’s console (enable it with npm start dev).

I think my problem was to rely too much on the output of the console. I never saw the output from console.log() in the socketNotificationReceived() (in main file) so I suspected a mistake with the socket notifications.

It’s strange that all console.logs() in socketNotificationReceived() are missing but now everything works.
Is it a feature?! ;D

If those are fine, what you can do is add console.log() at various places in your code to try and determine where it’s failing. Any console.log you add in node_helper.js will appear in the terminal where you started MM with npm start, and any console.log entries that you make in helloworld.js will appear in electron’s console (use npm start dev) to start electron with the dev console open.

so for example, in helloworld.js, maybe add this :

	start: function() {
		this.sendSocketNotification('CONFIG', this.config);
                console.log("notification sent to node_helper");
	},

and in node_helper.js

	socketNotificationReceived: function (notification, payload) {
		if (notification === 'CONFIG') {
                        console.log("CONFIG notification received");
			this.config = payload;
			this.sendSocketNotification('STARTED');
                        console.log("STARTED notification sent back to front end");
		}
	}

back in helloworld.js:

	socketNotificationReceived: function(notification, payload) {
		if (notification === 'STARTED') {
                        console.log("STARTED notification received from node_helper");
			this.config.text = 'Started';
			this.updateDom();
		}
	}

If you see all four of those messages, then the notifications are working and you need to look elsewhere. Otherwise, when one of the messages doesn’t show up when you expect it to, then you’ve now zeroed closer into the problem.

If you haven’t done so already, install MM locally on your laptop or workstation. It’s way easier to develop modules that way that directly on the Pi.

Try changing this:

this.sendSocketNotification('STARTED');

to this:

this.sendSocketNotification('STARTED', 'something');

See if that fixes it.