Explore fast path: fs.isFile and fs.isDirectory

[marvinhagemeister]

Original issue: #39

Module resolution typically involves a lot of file system calls. During the performance meeting on 23. Jan 2023 the idea was voiced to explore how much speedup could be gained via an optimized isFile or isDirectory function.

Example npm packages where such functions are used in the wild:

• resolve
• enhanced-resolve

[anonrig]

Question: What would you expect fs.isFile to return on a non-existing path?

[marvinhagemeister]

Question: What would you expect fs.isFile to return on a non-existing path?

I'd expect it to return false.

Found an isFile function in node itself that is used during ESM resolution. Looks like node would benefit from a dedicated isFile function too.

https://github.com/nodejs/node/blob/762a3a8ad925d56a12b43e0e7f7c811e93097784/lib/internal/modules/esm/resolve.js#L149-L151