Check config before starting MM (#3450)

I think it might be a good idea to check the config at every start.

CHANGELOG.md

@@ -11,6 +11,7 @@ _This release is scheduled to be released on 2024-10-01._
 
 ### Added
 
+- [core] Check config at every start of MagicMirror² (#3450)
 - [core] Add spelling check (cspell): `npm run test:spelling` and handle spelling issues
 - [core] removed `config.paths.vendor` (could not work because `vendor` is hardcoded in `index.html`), renamed `config.paths.modules` to `config.foreignModulesDir`, added variable `MM_CUSTOMCSS_FILE` which - if set - overrides `config.customCss`, added variable `MM_MODULES_DIR` which - if set - overrides `config.foreignModulesDir`
 - [core] elements are now removed from index.html when loading script or stylesheet files fails

js/app.js

@@ -117,6 +117,8 @@ function App () {
 			}
 		}
 
+		require(`${global.root_path}/js/check_config.js`);
+
 		try {
 			fs.accessSync(configFilename, fs.F_OK);
 			const c = require(configFilename);

js/check_config.js

@@ -64,12 +64,13 @@ function checkConfigFile () {
 		for (const error of errors) {
 			Log.error(`Line ${error.line} column ${error.column}: ${error.message}`);
 		}
-		return;
+		process.exit(1);
 	}
 
 	Log.info("Checking modules structure configuration... ");
 
 	const position_list = Utils.getModulePositions();
+
 	// Make Ajv schema configuration of modules config
 	// only scan "module" and "position"
 	const schema = {