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-rw-r--r--doc/api/stream.md32
1 files changed, 26 insertions, 6 deletions
diff --git a/doc/api/stream.md b/doc/api/stream.md
index 6510dec541..73659524ec 100644
--- a/doc/api/stream.md
+++ b/doc/api/stream.md
@@ -2559,6 +2559,7 @@ it is important to ensure the correct handling of backpressure and errors.
```js
const { once } = require('events');
+const finished = util.promisify(stream.finished);
const writable = fs.createWriteStream('./file');
@@ -2570,18 +2571,24 @@ const writable = fs.createWriteStream('./file');
}
writable.end();
// Ensure completion without errors.
- await once(writable, 'finish');
+ await finished(writable);
})();
```
-In the above, errors on the write stream would be caught and thrown by the two
-`once()` listeners, since `once()` will also handle `'error'` events.
+In the above, errors on `write()` would be caught and thrown by the
+`once()` listener for the `'drain'` event, since `once()` will also handle the
+`'error'` event. To ensure completion of the write stream without errors,
+it is safer to use the `finished()` method as above, instead of using the
+`once()` listener for the `'finish'` event. Under certain cases, an `'error'`
+event could be emitted by the writable stream after `'finish'` and as `once()`
+will release the `'error'` handler on handling the `'finish'` event, it could
+result in an unhandled error.
-Alternatively the readable stream could be wrapped with `Readable.from()` and
+Alternatively, the readable stream could be wrapped with `Readable.from()` and
then piped via `.pipe()`:
```js
-const { once } = require('events');
+const finished = util.promisify(stream.finished);
const writable = fs.createWriteStream('./file');
@@ -2589,7 +2596,20 @@ const writable = fs.createWriteStream('./file');
const readable = Readable.from(iterator);
readable.pipe(writable);
// Ensure completion without errors.
- await once(writable, 'finish');
+ await finished(writable);
+})();
+```
+
+Or, using `stream.pipeline()` to pipe streams:
+
+```js
+const pipeline = util.promisify(stream.pipeline);
+
+const writable = fs.createWriteStream('./file');
+
+(async function() {
+ const readable = Readable.from(iterator);
+ await pipeline(readable, writable);
})();
```