stream: add pipeline() for webstreams

Refs: #39316
PR-URL: #46307
Reviewed-By: Robert Nagy <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>

Author: debadree25

doc/api/stream.md

@@ -2696,6 +2696,9 @@ const cleanup = finished(rs, (err) => {
 <!-- YAML
 added: v10.0.0
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/46307
+    description: Added support for webstreams.
   - version: v18.0.0
     pr-url: https://github.com/nodejs/node/pull/41678
     description: Passing an invalid callback to the `callback` argument
@@ -2712,13 +2715,14 @@ changes:
     description: Add support for async generators.
 -->
 
-* `streams` {Stream\[]|Iterable\[]|AsyncIterable\[]|Function\[]}
-* `source` {Stream|Iterable|AsyncIterable|Function}
+* `streams` {Stream\[]|Iterable\[]|AsyncIterable\[]|Function\[]|
+  ReadableStream\[]|WritableStream\[]|TransformStream\[]}
+* `source` {Stream|Iterable|AsyncIterable|Function|ReadableStream}
   * Returns: {Iterable|AsyncIterable}
-* `...transforms` {Stream|Function}
+* `...transforms` {Stream|Function|TransformStream}
   * `source` {AsyncIterable}
   * Returns: {AsyncIterable}
-* `destination` {Stream|Function}
+* `destination` {Stream|Function|WritableStream}
   * `source` {AsyncIterable}
   * Returns: {AsyncIterable|Promise}
 * `callback` {Function} Called when the pipeline is fully done.

lib/internal/streams/pipeline.js

@@ -35,6 +35,9 @@ const {
   isReadable,
   isReadableNodeStream,
   isNodeStream,
+  isTransformStream,
+  isWebStream,
+  isReadableStream,
 } = require('internal/streams/utils');
 const { AbortController } = require('internal/abort_controller');
 
@@ -88,7 +91,7 @@ async function* fromReadable(val) {
   yield* Readable.prototype[SymbolAsyncIterator].call(val);
 }
 
-async function pump(iterable, writable, finish, { end }) {
+async function pumpToNode(iterable, writable, finish, { end }) {
   let error;
   let onresolve = null;
 
@@ -147,6 +150,35 @@ async function pump(iterable, writable, finish, { end }) {
   }
 }
 
+async function pumpToWeb(readable, writable, finish, { end }) {
+  if (isTransformStream(writable)) {
+    writable = writable.writable;
+  }
+  // https://streams.spec.whatwg.org/#example-manual-write-with-backpressure
+  const writer = writable.getWriter();
+  try {
+    for await (const chunk of readable) {
+      await writer.ready;
+      writer.write(chunk).catch(() => {});
+    }
+
+    await writer.ready;
+
+    if (end) {
+      await writer.close();
+    }
+
+    finish();
+  } catch (err) {
+    try {
+      await writer.abort(err);
+      finish(err);
+    } catch (err) {
+      finish(err);
+    }
+  }
+}
+
 function pipeline(...streams) {
   return pipelineImpl(streams, once(popCallback(streams)));
 }
@@ -259,7 +291,11 @@ function pipelineImpl(streams, callback, opts) {
         ret = Duplex.from(stream);
       }
     } else if (typeof stream === 'function') {
-      ret = makeAsyncIterable(ret);
+      if (isTransformStream(ret)) {
+        ret = makeAsyncIterable(ret?.readable);
+      } else {
+        ret = makeAsyncIterable(ret);
+      }
       ret = stream(ret, { signal });
 
       if (reading) {
@@ -303,7 +339,11 @@ function pipelineImpl(streams, callback, opts) {
           );
         } else if (isIterable(ret, true)) {
           finishCount++;
-          pump(ret, pt, finish, { end });
+          pumpToNode(ret, pt, finish, { end });
+        } else if (isReadableStream(ret) || isTransformStream(ret)) {
+          const toRead = ret.readable || ret;
+          finishCount++;
+          pumpToNode(toRead, pt, finish, { end });
         } else {
           throw new ERR_INVALID_RETURN_VALUE(
             'AsyncIterable or Promise', 'destination', ret);
@@ -324,12 +364,30 @@ function pipelineImpl(streams, callback, opts) {
         if (isReadable(stream) && isLastStream) {
           lastStreamCleanup.push(cleanup);
         }
+      } else if (isTransformStream(ret) || isReadableStream(ret)) {
+        const toRead = ret.readable || ret;
+        finishCount++;
+        pumpToNode(toRead, stream, finish, { end });
       } else if (isIterable(ret)) {
         finishCount++;
-        pump(ret, stream, finish, { end });
+        pumpToNode(ret, stream, finish, { end });
+      } else {
+        throw new ERR_INVALID_ARG_TYPE(
+          'val', ['Readable', 'Iterable', 'AsyncIterable', 'ReadableStream', 'TransformStream'], ret);
+      }
+      ret = stream;
+    } else if (isWebStream(stream)) {
+      if (isReadableNodeStream(ret)) {
+        finishCount++;
+        pumpToWeb(makeAsyncIterable(ret), stream, finish, { end });
+      } else if (isReadableStream(ret) || isIterable(ret)) {
+        finishCount++;
+        pumpToWeb(ret, stream, finish, { end });
+      } else if (isTransformStream(ret)) {
+        pumpToWeb(ret.readable, stream, finish, { end });
       } else {
         throw new ERR_INVALID_ARG_TYPE(
-          'val', ['Readable', 'Iterable', 'AsyncIterable'], ret);
+          'val', ['Readable', 'Iterable', 'AsyncIterable', 'ReadableStream', 'TransformStream'], ret);
       }
       ret = stream;
     } else {

lib/internal/streams/utils.js

@@ -77,6 +77,19 @@ function isWritableStream(obj) {
   );
 }
 
+function isTransformStream(obj) {
+  return !!(
+    obj &&
+    !isNodeStream(obj) &&
+    typeof obj.readable === 'object' &&
+    typeof obj.writable === 'object'
+  );
+}
+
+function isWebStream(obj) {
+  return isReadableStream(obj) || isWritableStream(obj) || isTransformStream(obj);
+}
+
 function isIterable(obj, isAsync) {
   if (obj == null) return false;
   if (isAsync === true) return typeof obj[SymbolAsyncIterator] === 'function';
@@ -303,6 +316,7 @@ module.exports = {
   isReadableFinished,
   isReadableErrored,
   isNodeStream,
+  isWebStream,
   isWritable,
   isWritableNodeStream,
   isWritableStream,
@@ -312,4 +326,5 @@ module.exports = {
   isServerRequest,
   isServerResponse,
   willEmitClose,
+  isTransformStream,
 };

lib/stream/promises.js

@@ -8,6 +8,7 @@ const {
 const {
   isIterable,
   isNodeStream,
+  isWebStream,
 } = require('internal/streams/utils');
 
 const { pipelineImpl: pl } = require('internal/streams/pipeline');
@@ -21,7 +22,7 @@ function pipeline(...streams) {
     let end;
     const lastArg = streams[streams.length - 1];
     if (lastArg && typeof lastArg === 'object' &&
-        !isNodeStream(lastArg) && !isIterable(lastArg)) {
+        !isNodeStream(lastArg) && !isIterable(lastArg) && !isWebStream(lastArg)) {
       const options = ArrayPrototypePop(streams);
       signal = options.signal;
       end = options.end;