[TS] GRPC Implementation (#6141)

* GRPC implementation for Typescript

* Fixes a couple of issues

* Finished implementing the typescript support for grpc

* Updated generated code

* Fixes CI

grpc/flatbuffers-js-grpc/src/server.ts

@@ -0,0 +1,40 @@
+import grpc from 'grpc';
+import { HelloReply, HelloRequest } from './greeter_generated';
+import { IGreeterServer, GreeterService } from './greeter_grpc';
+import { flatbuffers } from 'flatbuffers';
+
+class GreeterServer implements IGreeterServer {
+
+    SayHello(call: grpc.ServerUnaryCall<HelloRequest>, callback: grpc.sendUnaryData<HelloReply>): void {
+        console.log(`${call.request.name()}`);
+        const builder = new flatbuffers.Builder();
+        const offset = builder.createString(`welcome ${call.request.name()}`);
+        const root = HelloReply.createHelloReply(builder, offset);
+        builder.finish(root);
+        callback(null, HelloReply.getRootAsHelloReply(new flatbuffers.ByteBuffer(builder.asUint8Array())));
+    }
+
+    async SayManyHellos(call: grpc.ServerWritableStream<HelloRequest>): Promise<void> {
+        const name = call.request.name();
+        console.log(`${call.request.name()} saying hi in different langagues`);
+        ['Hi', 'Hallo', 'Ciao'].forEach(element => {
+            const builder = new flatbuffers.Builder();
+            const offset = builder.createString(`${element} ${name}`);
+            const root = HelloReply.createHelloReply(builder, offset);
+            builder.finish(root);
+            call.write(HelloReply.getRootAsHelloReply(new flatbuffers.ByteBuffer(builder.asUint8Array())))
+        });
+        call.end();
+    }
+}
+
+function serve(): void {
+    const PORT = 3000;
+    const server = new grpc.Server();
+    server.addService<IGreeterServer>(GreeterService, new GreeterServer());
+    console.log(`Listening on ${PORT}`);
+    server.bind(`localhost:${PORT}`, grpc.ServerCredentials.createInsecure());
+    server.start();
+}
+
+serve();