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Sync alternative to fs.openAsBlob #65462
Description
What is the problem this feature will solve?
I'm making a cross-runtime file streaming library (that needs to be fast) and this would make it way easier to do so since Bun.file() is already sync.
So the code might look like this if my suggestion made it to node:fs:
const getFile: (path: string) => File = globalThis.Bun
? Bun.file
: process.getBuiltinModule('fs').openAsWebFile;
// Usage
return new Response(getFile('./index.html'));
return new Response(getFile('./binary-data').slice(0, 100));What is the feature you are proposing to solve the problem?
A new API, something like fs.openAsWebFile() that returns a File maybe?
It would have more info for the Response constructor to pick up as well.
What alternatives have you considered?
fs.createReadStream but that is also async and can be slower too.
Activity
greenheadHQ commentedon Aug 27, 2026
Hi, I may be missing some context here, but
fs.openAsBlob()currently creates the file-backed Blob synchronously inside its implementation and then wraps it in a Promise.A previous attempt in #49759 also proposed
openAsBlobSync(), but it bundled that with changes to the existing API, and aCHANGES_REQUESTEDreview opposing those changes remained unresolved.It might also be worth confirming whether the current Promise-returning API is considered stable.
jasnell commentedon Aug 27, 2026
Yes, the current API is stable and won't be changed.
When I first introduced
openAsBlob(...), the original impl was sync but I was asked to make it return a promise. I'd be open to aopenAsBlobSyncaddition. PRs welcome.[-]Can `fs.openAsBlob` be sync?[/-][+]Sync alternative to `fs.openAsBlob`[/+]fs: add openAsBlobSync
fs: add openAsBlobSync