How to return grpc message results about grpc-web HOT 2 CLOSED

public getBook(): Promise<any> {
  const getBookRequest = new GetBookRequest();
  getBookRequest.setIsbn(60929871);
  const requestPromise = new Promise<any>((resolve, reject) => {
            grpc.unary(BookService.GetBook, {
                request: getBookRequest,
                host: host,
                onEnd: (res) => {
                    const {status, statusMessage, headers, message, trailers} = res;
                    if (status === Code.OK && message) {
                         console.log("getBook.onEnd.message", message.toObject());
                         resolve(message.toObject());
                     }
                },
            });
        });
  return requestPromise;
}

public async someFunction(): Promise<any> {
  book: any = await getBook();
  // do binding here 
  ...
}

getBook().then(function(result) {
   book: any = result;
   // do binding here
    ...
});