Preserve nested YAML variables and add importer/exporter regression tests

src/utils/yamlImporter.ts

@@ -140,7 +140,7 @@ export const parseButtonCardYaml = (yamlString: string): Partial<ButtonConfig> =
   if (parsed.variables && typeof parsed.variables === 'object') {
     config.variables = Object.entries(parsed.variables).map(([name, value]) => ({
       name,
-      value: String(value)
+      value: value !== null && typeof value === 'object' ? JSON.stringify(value) : String(value)
     }));
   }
 

tests/yamlRoundTrip.test.cjs

@@ -0,0 +1,88 @@
+'use strict';
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const ts = require('typescript');
+const YAML = require('yaml');
+
+// Run the actual TypeScript importer and generator without duplicating their logic.
+require.extensions['.ts'] = (module, filename) => {
+  const source = fs.readFileSync(filename, 'utf8');
+  const compiled = ts.transpileModule(source, {
+    fileName: filename,
+    compilerOptions: { module: ts.ModuleKind.CommonJS, target: ts.ScriptTarget.ES2022, esModuleInterop: true },
+  });
+  module._compile(compiled.outputText, filename);
+};
+
+const { parseButtonCardYaml, validateImportedConfig } = require('../src/utils/yamlImporter.ts');
+const { generateYaml } = require('../src/utils/yamlGenerator.ts');
+const { DEFAULT_CONFIG } = require('../src/types.ts');
+
+function roundTrip(source) {
+  const imported = validateImportedConfig(parseButtonCardYaml(YAML.stringify(source)));
+  const generated = generateYaml({ ...DEFAULT_CONFIG, ...imported });
+  return { imported, generated, parsed: YAML.parse(generated) };
+}
+
+test('retains entity, icon, name, and essential show flags', () => {
+  const { parsed } = roundTrip({
+    type: 'custom:button-card',
+    entity: 'light.kitchen',
+    name: 'Kitchen',
+    icon: 'mdi:lightbulb',
+    show_name: false,
+    show_icon: false,
+  });
+  assert.equal(parsed.entity, 'light.kitchen');
+  assert.equal(parsed.name, 'Kitchen');
+  assert.equal(parsed.icon, 'mdi:lightbulb');
+  assert.equal(parsed.show_name, false);
+  assert.equal(parsed.show_icon, false);
+});
+
+test('preserves nested variable objects and arrays without object-string coercion', () => {
+  const vars = {
+    values: { thresholds: [20, 50, 75], colors: { low: '#123456', high: '#abcdef' } },
+    options: ['one', 'two'],
+  };
+  const { imported, parsed, generated } = roundTrip({
+    type: 'custom:button-card',
+    entity: 'sensor.temperature',
+    variables: vars,
+  });
+  assert.deepEqual(JSON.parse(imported.variables.find(v => v.name === 'values').value), vars.values);
+  assert.deepEqual(parsed.variables, vars);
+  assert.equal(generated.includes('[object Object]'), false);
+});
+
+test('preserves action targets and service data', () => {
+  const { parsed } = roundTrip({
+    type: 'custom:button-card',
+    entity: 'switch.fan',
+    tap_action: {
+      action: 'perform-action',
+      perform_action: 'light.turn_on',
+      target: { entity_id: ['light.kitchen', 'light.table'] },
+      data: { brightness_pct: 45 },
+    },
+  });
+  assert.equal(parsed.tap_action.perform_action, 'light.turn_on');
+  assert.deepEqual(parsed.tap_action.target, { entity_id: ['light.kitchen', 'light.table'] });
+  assert.equal(parsed.tap_action.data.brightness_pct, 45);
+});
+
+test('retains JavaScript action templates', () => {
+  const code = '[[[ return entity.state === "on"; ]]]';
+  const { parsed } = roundTrip({
+    type: 'custom:button-card', entity: 'switch.lamp',
+    tap_action: { action: 'javascript', javascript: code },
+  });
+  assert.equal(parsed.tap_action.action, 'javascript');
+  assert.equal(parsed.tap_action.javascript.trim(), code);
+});
+
+test('rejects invalid YAML instead of fabricating an empty configuration', () => {
+  assert.throws(() => parseButtonCardYaml('entity: [unterminated'), /./);
+});