client.js

 client = new HelloServiceClient("http://localhost:8080", null, {format: 'text'});

			 let getRequest = new HelloRequest();
			 getRequest.setName(message);
       // it sends header 'application/grpc-web-text' but Armeria expects 'application/protobuf'
			 client.hello(getRequest, (err, response) => {
			        console.log('response', response)
					let reply = response.toObject().HelloReply;
					console.log(reply.message);
			 });

Main.java

import com.linecorp.armeria.common.HttpHeaderNames;
import com.linecorp.armeria.common.HttpMethod;
import com.linecorp.armeria.common.grpc.GrpcSerializationFormats;
import com.linecorp.armeria.common.grpc.protocol.GrpcHeaderNames;
import com.linecorp.armeria.server.HttpServiceWithRoutes;
import com.linecorp.armeria.server.Server;
import com.linecorp.armeria.server.cors.CorsServiceBuilder;
import com.linecorp.armeria.server.docs.DocServiceBuilder;
import com.linecorp.armeria.server.docs.DocServiceFilter;
import com.linecorp.armeria.server.grpc.GrpcService;
import com.linecorp.armeria.server.logging.LoggingService;
import example.armeria.grpc.Hello;
import example.armeria.grpc.HelloServiceGrpc;
import io.grpc.protobuf.services.ProtoReflectionService;
import io.grpc.reflection.v1alpha.ServerReflectionGrpc;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public final class Main {

	private static final Logger logger = LoggerFactory.getLogger(Main.class);

	public static void main(String[] args) throws Exception {
		final Server server = newServer(8080, 8443);

		Runtime.getRuntime().addShutdownHook(new Thread(() -> {
			server.stop().join();
			logger.info("Server has been stopped.");
		}));

		server.start().join();

		logger.info("Server has been started. Serving DocService at http://127.0.0.1:{}/docs",
				server.activeLocalPort());
	}

	static Server newServer(int httpPort, int httpsPort) throws Exception {

		final CorsServiceBuilder corsBuilder =
				CorsServiceBuilder.forOrigin("*")
						.allowRequestMethods(HttpMethod.values()) // Allow POST method.
						// Allow Content-type and X-GRPC-WEB headers.
						.allowRequestHeaders(
								HttpHeaderNames.CONTENT_TYPE,
								HttpHeaderNames.of("X-GRPC-WEB"),
								HttpHeaderNames.of("x-user-agent")
						)
						// Expose trailers of the HTTP response to the client.
						.exposeHeaders(
								GrpcHeaderNames.GRPC_STATUS,
								GrpcHeaderNames.GRPC_MESSAGE,
								GrpcHeaderNames.ARMERIA_GRPC_THROWABLEPROTO_BIN
								);

		final Hello.HelloRequest exampleRequest = Hello.HelloRequest.newBuilder().setName("Armeria").build();
		final HttpServiceWithRoutes grpcService =
				GrpcService.builder()
						.addService(new HelloServiceImpl())
						// See https://github.com/grpc/grpc-java/blob/master/documentation/server-reflection-tutorial.md
						.addService(ProtoReflectionService.newInstance())
						.supportedSerializationFormats(GrpcSerializationFormats.values())
						.enableUnframedRequests(true)
						// You can set useBlockingTaskExecutor(true) in order to execute all gRPC
						// methods in the blockingTaskExecutor thread pool.
						// .useBlockingTaskExecutor(true)
						.build();
		return Server.builder()
				.http(httpPort)
				.https(httpsPort)
				.tlsSelfSigned()
				.service(grpcService,  corsBuilder.newDecorator(),  LoggingService.newDecorator())
				// You can access the documentation service at http://127.0.0.1:8080/docs.
				// See https://line.github.io/armeria/server-docservice.html for more information.
				.serviceUnder("/docs",
						new DocServiceBuilder()
								.exampleRequestForMethod(HelloServiceGrpc.SERVICE_NAME,
										"Hello", exampleRequest)
								.exampleRequestForMethod(HelloServiceGrpc.SERVICE_NAME,
										"LazyHello", exampleRequest)
								.exampleRequestForMethod(HelloServiceGrpc.SERVICE_NAME,
										"BlockingHello", exampleRequest)
								.exclude(DocServiceFilter.ofServiceName(
										ServerReflectionGrpc.SERVICE_NAME))
								.build()
				)
				.build();
	}

	private Main() {}
}