alt Hacker NewsThe yt-dlp project uses Deno as its default and preferred JavaScript runtime when downloading YouTube videos (this replaced their own handwritten JS interpreter). Fortunately yt-dlp also has support for Node and QuickJS as well as deprecated support for Bun, but I don’t think any of those were preferred by the project for various reasons such as portability, security and I think also speed.
See https://github.com/yt-dlp/yt-dlp/issues/14404, https://github.com/yt-dlp/yt-dlp/issues/15012, and https://github.com/yt-dlp/yt-dlp/wiki/EJS.
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For asynchronous downloading of huge media files, speed should not be a priority?
As I recall, they picked Deno over Bun during the whole vibecoding rewrite fiasco from six months ago, and there wasn't a ton of explanation given beyond the general vibe of "ai bad". They might reevaluate that in light of things being generally fine and losing their precious handcoded runtime choice.
QuickJS works fine for yt-dlp and is way smaller: less than 1 MB vs 34 MB + its many dependencies for Deno.
See https://github.com/denoland/deno/discussions/9811