Add `session` package

[mjackson]

This package is a standalone version of Remix v1's session handling.

Current code can be found here.

It should also include some concrete implementations of session storage interfaces, including one for the filesystem and one for Redis.

[brophdawg11]

#10797

[brophdawg11]

including one for the filesystem

How do you envision this without introducing a dependency on node's fs APIs? One option would be a simple DI approach:

let { getSession, commitSession } = createFileSessionStorage({
  cookie: { secrets: ['secret1'] },
  readFile: fs.readFile,
  writeFile: fs.writeFile,
  deleteFile: fs.unlink,
  mkdir: fs.mkdir,
})

[sergiodxa]

If you're going to use the same names as node:fs I would suggest accepting a fs key directly so you can do:

import * as fs from "node:fs/promises";

let { getSession, commitSession } = createFileSessionStorage({
  cookie: { secrets: ['secret1'] },
  fs, // use the imported one automatically
})

And only if you want to use a custom fs implementation provide the whole thing:

let { getSession, commitSession } = createFileSessionStorage({
  cookie: { secrets: ['secret1'] },
  fs: { readFile, writeFile, unlink, mkdir } // implement yourself
})

So the most common use case is simpler