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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Dealing with async errors during `_read()`","articleBody":"I feel like there is something missing in the streams `_read` API for implementors.\r\n\r\nBasically the current state of things is that stream implementors need to implement async error handling something like this:\r\n\r\n```js\r\n_read (n) {\r\n  doAsyncRead(n, (err, buf) =\u003e {\r\n    if (err) {\r\n      if (this._readableState.autoDestroy) {\r\n        this.destroy(err)\r\n      } else {\r\n        this.emit('error', err)\r\n      }\r\n    } else {\r\n      this.push(buf)\r\n    }\r\n  })\r\n}\r\n```\r\n\r\nThere are some problems with this:\r\n\r\n1. Most stream implementors don't do this and simply don't bother to conform to the `autoDestroy` option and either `destroy()` or `emit('error', err)`, which one they choose is mostly unclear and undocumented.\r\n2. Even when conforming you either have to access the `_readableState` object or add a flag based on the options sent to the `Readable` super.\r\n\r\nI'm not quite sure how to resolve this. I can think of a few ways:\r\n\r\n1. Add a `cb` to `_read` that can be invoked with an error and would internally call the `errorOrDestroy` method.\r\n2. Make the `errorOrDestroy` util directly accessible for stream implementors and document it somehow.\r\n3. Leave as is and clarify in documentation how to handle this scenario (preferable without `_readableState`).\r\n4. Deprecate `autoDestroy` and make it `true` by default.\r\n5. Document that `autoDestroy` is for stream implementors only and not for stream consumers.","author":{"url":"https://github.com/ronag","@type":"Person","name":"ronag"},"datePublished":"2019-09-16T20:23:17.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/29584/node/issues/29584"}