example.ts

const someFunc = ({ context }: ResolverData) => {
  (context as any).value2 = "another value";
};

const addToContext: MiddlewareFn = (data, next) => {
  (data.context as any).value = "new value";
  someFunc(data);
  return next();
};

@Query(() => String)
@UseMiddleware(addToContext)
async hello(@Ctx() ctx: any) {
  return ctx.value + ctx.value2;
}