feat(smartduplex): improve backpressure handling and web/node stream interoperability

test/test.utilities.ts

@@ -0,0 +1,51 @@
+import { expect, tap } from '@push.rocks/tapbundle';
+import { createTransformFunction, createPassThrough, SmartDuplex, StreamWrapper } from '../ts/index.js';
+
+// =============================================
+// createTransformFunction
+// =============================================
+
+tap.test('createTransformFunction: should create a transform stream', async (tools) => {
+  const doubler = createTransformFunction<number, number>(async (n) => n * 2, { objectMode: true });
+  const results: number[] = [];
+
+  doubler.on('data', (chunk: number) => results.push(chunk));
+
+  const done = tools.defer();
+  doubler.on('end', () => {
+    expect(results).toContain(10);
+    expect(results).toContain(20);
+    expect(results).toContain(30);
+    done.resolve();
+  });
+
+  doubler.write(5);
+  doubler.write(10);
+  doubler.write(15);
+  doubler.end();
+  await done.promise;
+});
+
+// =============================================
+// createPassThrough
+// =============================================
+
+tap.test('createPassThrough: should pass data through unchanged', async (tools) => {
+  const passThrough = createPassThrough();
+  const results: string[] = [];
+
+  passThrough.on('data', (chunk: string) => results.push(chunk));
+
+  const done = tools.defer();
+  passThrough.on('end', () => {
+    expect(results).toEqual(['hello', 'world']);
+    done.resolve();
+  });
+
+  passThrough.write('hello');
+  passThrough.write('world');
+  passThrough.end();
+  await done.promise;
+});
+
+export default tap.start();