preserveSymlinks: Changes to target module are not propagated to symlink modules

[aleclarson]

TypeScript Version: 3.4.0-dev.20190316

Search Terms:

• preserveSymlinks, symlink, watch, change

Description:

I'm not familiar with how preserveSymlinks works internally, but it appears that symlink modules are not notified of changes to their target path.

My scenario is the following: I'm linking from node_modules/foo to a package that exists outside my project's root directory. When I update foo/src/index.ts, my project is not aware until I restart the TS server.

Related Issues: None.

[sheetalkamat]

That would be intended behavior with --preserveSymlinks wherein we only look at the symlink and its change and not the target.

[aleclarson]

That's frankly not good enough. The current behavior makes it much harder to iterate on packages when using a yarn link workflow. I'll assume Microsoft doesn't care about symlinks (most big companies don't for some reason) until this is fixed.

[aleclarson]

Also, cross-package refactors are not possible when using symlinks.

[ChristianIvicevic]

This is an issue I just came across myself in a workflow wherein I am using yarn workspaces in a monorepo. I am referencing a linked sub-package and ts-node had issues verifying my files since there was no declaration file. Hence I enabled preserveSymlinks and just recently noticed the issue that my main package isn't picking up any changes. Surprisingly enough, running tsc --watch and importing the generated output files made the parent aware of changes but I dislike this workflow since I do not want to transpile the library and rather import it directly.

[jacksteamdev]

YMMV with different build tools. I'm using preserveSymlinks in a yarn workspace monorepo with success. Both ts-node-dev and webpack pick up changes to symlinked sub-packages.

Just make sure that main in the package.json of the linked sub-package points to the correct ts file. Webpack may also require additional configuration.