Improve error message when reading invalid YAML file.

lib/util/yaml.js

@@ -2,7 +2,23 @@ const yaml = require('js-yaml');
 const fs = require('fs');
 
 function read(file) {
-    return yaml.safeLoad(fs.readFileSync(file, 'utf8'));
+    try {
+        return yaml.safeLoad(fs.readFileSync(file, 'utf8'));
+    } catch (error) {
+        if (error.name === 'YAMLException') {
+            error.message =
+                `\n\n\n` +
+                `\t====================================================================\n` +
+                `\tYour YAML file '${file}' is invalid\n` +
+                `\tUse e.g. https://jsonformatter.org/yaml-validator to find and fix the issue.\n` +
+                `\t====================================================================\n` +
+                `\n\n` +
+                error.message;
+        }
+
+
+        throw error;
+    }
 }
 
 function readIfExists(file) {

test/settings.test.js

@@ -394,4 +394,31 @@ describe('Settings', () => {
         settings.banDevice('0x1234');
         expect(settings.get().ban).toStrictEqual(['0x123', '0x1234']);
     });
+
+    it('Should throw error when yaml file is invalid', () => {
+        fs.writeFileSync(configurationFile, `
+             good: 9
+             \t wrong
+        `)
+
+        let error;
+        try {
+            settings._reRead();
+        } catch (e) {
+            error = e;
+        }
+
+        expect(error.message).toContain(`Your YAML file '${configurationFile}' is invalid`);
+    });
+
+    it('Should throw error when yaml file does not exist', () => {
+        let error;
+        try {
+            settings._reRead();
+        } catch (e) {
+            error = e;
+        }
+
+        expect(error.message).toContain(`no such file or directory, open`);
+    });
 });