@Klinge
I had the same issue with MMM-Universal-Pir.
The maker had made a comment ABOUT It in the readme, with the correct commands after mine e-mail.
Read the readme and you are How to do.

@sdetweil In the netherlands, we do have that!
Fortunately, otherwise I would not have been able to write this MagicMirror module ;-)

MMM-MyHomeWizard is a MagicMirror module that shows the information from the HomeWizard P1 meter and/or the HomeWizard WaterMeter.
The HomeWizard P1 Meter gives you detailed insight into your gas consumption, electricity consumption and solar surplus.
The HomeWizard Watermeter gives you live insight into your water consumption.

Homepage: MMM-MyHomeWizard

@sdetweil
Meanwhile I was doing this, and I found the error (stupid me)

	start: function () {
		Log.info("Starting module: " + this.name);
		requiresVersion: "2.9.0";	
			
		// Set locales

		if (this.config.P1_IP != null) {
			this.urlP1 = "http://" + this.config.P1_IP + "/api/v1/data/";
		} else {
			this.urlP1 = "https://dummyjson.com/c/7e24-36ab-48e0-a96d";
		}

		if (this.config.WM_IP != null) {
			this.urlWM = "http://" + this.config.WM_IP + "/api/v1/data/";
		} else {
			this.urlWM = "https://dummyjson.com/c/704a-9a96-4845-bc72";
		}
//		this.urlP1 = "http://" + this.config.P1_IP + "/api/v1/data/";
//		this.urlWM = "http://" + this.config.WM_IP + "/api/v1/data/";
		
    		this.MHW_P1 = [];	        // <-- Create empty MHW_P1 array
		this.MHW_WM = [];		// <-- Create empty MHW_WM array
		this.scheduleUpdate();       	// <-- When the module updates (see below)
	},

The line with "requiresVersion: “2.9.0”; " was ending with an “,” instead of “;”

without the “if” statement, I don’t get a failure with a “,”
So changed it now into “;” and everythins seems to work.
I continue testing.

@MMRIZE Thanks for the alternative way. I’m going to look into it.
So with the “promise” statement, it looks like I can eleminate the node_helper.js

@sdetweil
In the console - sources it says:

Uncaught SyntaxError: Unexpected token 'if'

@sdetweil

	// Default values
	defaults: {
		P1_IP: null,				// IP Address P1 Meter
		WM_IP: null,				// IP Address Water Meter
		maxWidth: "500px",			// Max width wrapper
		extraInfo: false,			// Show extra information
		showFooter: false,			// Show footer (name Power Meter)
		currentPower: true,			// Show current power usage
		initialLoadDelay: 1000,
		updateInterval: 10000			// Every 10 seconds
	},

In the script it will assume you have 2 different IP addresses to query an URL.
1 IP for the HomeWizard P1 meter
1 IP for the HomeWizard Water Meter
This is because I like to show the information of both in 1 script. Everything works fine if both are used, but when someone only has the P1 meter, the IP for the Water Meter is not used and results in a console fetch error (normal behavior)

[ERROR] Error: TypeError: fetch failed
    at node:internal/deps/undici/undici:13178:13
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
  [cause]: Error: getaddrinfo ENOTFOUND null
      at GetAddrInfoReqWrap.onlookupall [as oncomplete] (node:dns:120:26) {
    errno: -3008,
    code: 'ENOTFOUND',
    syscall: 'getaddrinfo',
    hostname: 'null'
  }
} 

Is there a way to switch URL in case one of both URL are NULL? I’ve tried, but it doesn’t work with if-else

	start: function () {
		Log.info("Starting module: " + this.name);
		requiresVersion: "2.9.0",	
			
		// Set locales
		if (this.config.P1_IP != null) {
			this.urlP1 = "http://" + this.config.P1_IP + "/api/v1/data/";
		} else {
			this.urlP1 = "https://dummyjson.com/c/7e24-36ab-48e0-a96d";
		}

		if (this.config.WM_IP != null) {
			this.urlWM = "http://" + this.config.WM_IP + "/api/v1/data/";
		} else {
			this.urlWM = "https://dummyjson.com/c/704a-9a96-4845-bc72";
		}
		
    		this.MHW_P1 = [];	        // <-- Create empty MHW_P1 array
		this.MHW_WM = [];		// <-- Create empty MHW_WM array
		this.scheduleUpdate();       	// <-- When the module updates (see below)
	},

@MMRIZE Thanks for your reaction.

@sdetweil Thnx, you helped me a lot!!

@sdetweil Wow, it works!
Just checking, it has to be done in node_helper and the MMM-Module?