stream: ensure text() stream consumer flushes correctly

Signed-off-by: James M Snell <jasnell@gmail.com> PR-URL: #39737 Reviewed-By: Robert Nagy <ronagy@icloud.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
nodejs · Aug 16, 2021 · cd9b0bf · cd9b0bf
1 parent 03be967
commit cd9b0bf
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diff --git a/lib/stream/consumers.js b/lib/stream/consumers.js
@@ -63,6 +63,9 @@ async function text(stream) {
     else
       str += dec.decode(chunk, { stream: true });
   }
+  // Flush the streaming TextDecoder so that any pending
+  // incomplete multibyte characters are handled.
+  str += dec.decode(undefined, { stream: false });
   return str;
 }
 

diff --git a/test/parallel/test-stream-consumers.js b/test/parallel/test-stream-consumers.js
@@ -232,3 +232,17 @@ const kArrayBuffer =
   stream.write({});
   stream.end({});
 }
+
+{
+  const stream = new TransformStream();
+  text(stream.readable).then(common.mustCall((str) => {
+    // Incomplete utf8 character is flushed as a replacement char
+    assert.strictEqual(str.charCodeAt(0), 0xfffd);
+  }));
+  const writer = stream.writable.getWriter();
+  Promise.all([
+    writer.write(new Uint8Array([0xe2])),
+    writer.write(new Uint8Array([0x82])),
+    writer.close(),
+  ]).then(common.mustCall());
+}