address PR comments

packages/core/src/__tests__/utils.test.ts

@@ -5,6 +5,7 @@ describe('isObjectLiteral', () => {
 		['empty object literal', {}, true],
 		['object with properties', { foo: 'bar', num: 123 }, true],
 		['nested object literal', { nested: { foo: 'bar' } }, true],
+		['object with symbol key', { [Symbol.for('foo')]: 'bar' }, true],
 		['null', null, false],
 		['empty array', [], false],
 		['array with values', [1, 2, 3], false],
@@ -23,6 +24,7 @@ describe('isObjectLiteral', () => {
 		['Object.create(null)', Object.create(null), false],
 		['Buffer', Buffer.from('test'), false],
 		['Serialized Buffer', Buffer.from('test').toJSON(), true],
+		['Promise', new Promise(() => {}), false],
 	])('should return %s for %s', (_, input, expected) => {
 		expect(isObjectLiteral(input)).toBe(expected);
 	});

packages/core/src/utils.ts

@@ -1,4 +1,4 @@
-type ObjectLiteral = { [key: string]: unknown };
+type ObjectLiteral = { [key: string | symbol]: unknown };
 
 /**
  * Checks if the provided value is a plain object literal (not null, not an array, not a class instance, and not a primitive).