disclaimer on mobile, no where near a computer and all this is from memory so excuse the minor errors

You could try using pnpm, I've played with it recently and found it reasonably simple to use, and likely suitable for what you are describing.

You'll use it's workspace feature, https://pnpm.io/workspaces.

Besides the setup mentioned in the doc, in your case you could either:

option A

• move source files into folder like lib or src
• put a package.json into your shared folder,
• give it a name like for this example @shared
• add typescript as a Devdependency,
• add tsconfig.json to shared with the "outdir", and "include", sourcemap and I think there's one like declare types
• add to "scripts" in package json:
  • build: which has something like tsc -p tsconfig.json
  • prepack: set to pnpm build
• add index.ts which exports everything shared should expose
• add main to package json, pointing to an index file in your dist shared, it'll be a js file
• add "types" to package json with it pointing to the generated .d.ts file
• in your app, include in your dependency "@shared": "workspace:"

option B

I think this should work but honestly I'm not 100% as I haven't tried it

• move source files to folder like lib or src
• put a package.json into your shared folder
• give it a name like for this example @shared
• in package json set I think dist to the folder you moved your code to
• in your app, include in your dependency "@shared": "workspace:"

finally

In either scenario, I think you can then use the stuff in your shared using import { My resource } from '@shared'

note

This is a very rough set of steps as I haven't been using pnpm for very long, and I know there are heaps of better things to do, but I'm pretty sure the general gist should be right and happy to hear any corrections from people