Method decorate

packages/metadata/src/reflect.ts:163–179

(
    decorators: (PropertyDecorator | MethodDecorator)[] | ClassDecorator[],
    target: Object,
    targetKey?: string | symbol,
    descriptor?: PropertyDescriptor,
  )

  ): PropertyDescriptor | Function;

  decorate(
    decorators: (PropertyDecorator | MethodDecorator)[] | ClassDecorator[],
    target: Object,
    targetKey?: string | symbol,
    descriptor?: PropertyDescriptor,
  ): PropertyDescriptor | Function {
    if (targetKey) {
      return Reflect.decorate(
        <(PropertyDecorator | MethodDecorator)[]>decorators,
        target,
        targetKey,
        descriptor,
      );
    } else {
      return Reflect.decorate(<ClassDecorator[]>decorators, <Function>target);
    }
  }

  metadata(
    metadataKey: string,