use defineProperty

src/decorators/register.ts

@@ -146,17 +146,23 @@ export function SchemaClass<T>(originalClass: ClassType<T>) {
   });
   Object.setPrototypeOf(newClass, originalClass.prototype);
   for (const field of schemaFields) {
-    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-    // @ts-ignore
-    newClass[field] = schema[field];
+    Object.defineProperty(newClass, field, {
+      configurable: true,
+      enumerable: true,
+      writable: true,
+      value: schema[field],
+    });
   }
   for (const functionField of schemaFunctions) {
     if (newClass[functionField]) {
       continue;
     }
-    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-    // @ts-ignore
-    newClass[functionField] = Schema.prototype[functionField];
+    Object.defineProperty(newClass, functionField, {
+      configurable: true,
+      enumerable: false,
+      writable: false,
+      value: Schema.prototype[functionField],
+    });
   }
 
   newClass[kSchema] = true;

tests/register-schema.spec.ts

@@ -41,4 +41,10 @@ describe('Schema registration', () => {
   it('should throw if required field is missing', () => {
     expect(() => new ConfigWithRequiredFields({})).toThrow();
   });
+
+  it('should act functions of schema', () => {
+    const schema = Config as Schema<Config>;
+    const newSchema = schema.description('foo');
+    expect(newSchema.meta.description).toBe('foo');
+  });
 });