test: Added test for piped streams

src/json-rpc/json-rpc-client.ts

@@ -110,9 +110,9 @@ export class JsonRpcClient<API extends MethodInterface = Record<string, any>> {
 		}
 	}
 
-	toStreamPair(): { input: WritableStream<string>, output: ReadableStream<string> } {
-		const input = new WritableStream<string>({ write: message => this.accept(message) });
-		const output = new ReadableStream<string>({ start: controller => this.onrequest = message => controller.enqueue(message) });
-		return { input, output };
+	toStream(): ReadableWritablePair<string, string> {
+		const readable = new ReadableStream<string>({ start: controller => this.onrequest = message => controller.enqueue(message) });
+		const writable = new WritableStream<string>({ write: message => this.accept(message) });
+		return { readable, writable };
 	}
 }

src/json-rpc/json-rpc-dual-engine.ts

@@ -27,7 +27,7 @@ export class JsonRpcDualEngine<RemoteAPI extends MethodInterface = any> {
 		}
 	}
 
-	toStream(): TransformStream<string, string> {
+	toStream(): ReadableWritablePair<string, string> {
 		return new TransformStream({
 			start: controller => this.onmessage = response => controller.enqueue(response),
 			transform: message => this.accept(message),

src/json-rpc/json-rpc-server.test.ts

@@ -1,4 +1,4 @@
-import { expect} from 'expect';
+import { expect } from 'expect';
 import { beforeEach, describe, it, mock } from 'node:test';
 import { JsonRpcServer } from './json-rpc-server.js';
 
@@ -94,4 +94,29 @@ describe(JsonRpcServer.name, () => {
 
 		expect(parsed).toEqual({ jsonrpc: '2.0', result: 'pong', id: 1 });
 	});
+
+	it('should work as a piped stream', async () => {
+		const input = new ReadableStream({
+			start(controller) {
+				controller.enqueue(JSON.stringify({ jsonrpc: '2.0', method: 'ping', id: 1 }));
+				controller.close();
+			},
+		});
+		const stream = server.toStream();
+		const output = new WritableStream<string>({
+			start() {
+				this.chunks = [];
+			},
+			write(chunk) {
+				this.chunks.push(chunk);
+			},
+			close() {
+				expect(this.chunks).toEqual([JSON.stringify({ jsonrpc: '2.0', result: 'pong', id: 1 })])
+			},
+		});
+
+		expect.assertions(1);
+
+		await input.pipeThrough(stream).pipeTo(output);
+	});
 });