Executing BookService gRPC

BookService.js

import { grpc } from "@improbable-eng/grpc-web";
import { BookService } from "./Book_pb_service";

parseGetBookMessage = message => {
  // parse the binary response back to appropriate type described in the proto
  const book = {
    isbn: message.getIsbn(),
    title: message.getTitle(),
    author: message.getAuthor()
  };
  return book;
};

export const getBookDetails = () => {
  // domain where the service is hosted
  const host = "http://localhost:5489";

  // selecting the method from the service
  const methodDescriptor = BookService.GetBook;

  // constructing the request class
  const request = new methodDescriptor.requestType();

  // setting the body for request
  request.setIsbn(325);

  // options for the grpc call
  const options = {
    host,
    request,
    // callback to be executed when the API call is completed
    onEnd: response => {
      const { status, statusMessage, headers, message, trailers } = response;
      if (status === grpc.Code.OK && message) {
        const book = parseGetBookMessage(message);
        console.log("all ok. got book: ", book);
      }
      console.log("error.code", status, "error.message", statusMessage);
    }
  };

  return grpc.unary(methodDescriptor, options);
};