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learn: Update Don't Block the Event Loop outdated remark about fs.readFile() #7493

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avivkeller merged 3 commits into from
Mar 19, 2025
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learn: Update Don't Block the Event Loop outdated remark about fs.readFile() #7493

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Update dont-block-the-event-loop.md
thiagopromano Feb 12, 2025
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Update dont-block-the-event-loop.md
thiagopromano Feb 12, 2025
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Update dont-block-the-event-loop.md
thiagopromano Feb 12, 2025
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2 changes: 1 addition & 1 deletion apps/site/pages/en/learn/asynchronous-work/dont-block-the-event-loop.md
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Expand Up @@ -436,7 +436,7 @@ Two examples should illustrate the possible variation in task times.

Suppose your server must read files in order to handle some client requests.
After consulting the Node.js [File system](https://nodejs.org/api/fs.html) APIs, you opted to use `fs.readFile()` for simplicity.
However, `fs.readFile()` is ([currently](https://github.com/nodejs/node/pull/17054)) not partitioned: it submits a single `fs.read()` Task spanning the entire file.
However, `fs.readFile()` before v10 was not partitioned: it submitted a single `fs.read()` Task spanning the entire file.
If you read shorter files for some users and longer files for others, `fs.readFile()` may introduce significant variation in Task lengths, to the detriment of Worker Pool throughput.

For a worst-case scenario, suppose an attacker can convince your server to read an _arbitrary_ file (this is a [directory traversal vulnerability](https://www.owasp.org/index.php/Path_Traversal)).
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