backend-and-orchestration-toolkit/code/protocol_demos/grpc-demo/server.js

const grpc = require("grpc");
const protoLoader = require("@grpc/proto-loader")
const packageDef = protoLoader.loadSync("todo.proto", {});
const grpcObject = grpc.loadPackageDefinition(packageDef);
const todoPackage = grpcObject.todoPackage;

const server = new grpc.Server();
server.bind("0.0.0.0:40000",
 grpc.ServerCredentials.createInsecure());

server.addService(todoPackage.Todo.service,
    {
        "createTodo": createTodo,
        "readTodos" : readTodos,
        "readTodosStream": readTodosStream
    });
server.start();

const todos = []
function createTodo (call, callback) {
    const todoItem = {
        "id": todos.length + 1,
        "text": call.request.text
    }
    todos.push(todoItem)
    callback(null, todoItem);
}

function readTodosStream(call, callback) {
    
    todos.forEach(t => call.write(t));
    call.end();
}


function readTodos(call, callback) {
    callback(null, {"items": todos})   
}