Cannot find module 'ts-node' (yarn)

[ntucker]

Bug report

Actual Behavior

Attempts to build using this loader result in the following:

! Module build failed: Error: Cannot find module 'ts-node'
ERR! Require stack:
ERR! - /home/circleci/project/node_modules/cosmiconfig-typescript-loader/dist/cjs/index.js

Expected Behavior

https://github.com/Codex-/cosmiconfig-typescript-loader/blob/main/package.json#LL39C6-L39C13

cosmiconfig-typescript-loader has a peerDep of ts-node. This module has cosmiconfig-typescript-loader as a dependency - therefore it should specify ts-node as a dependency as well.

How Do We Reproduce?

ntucker/anansi#1941

https://app.circleci.com/pipelines/github/ntucker/anansi/9024/workflows/561c1fc3-70c1-403c-a033-8175c9788786/jobs/47985

Please paste the results of npx webpack info here, and mention other relevant information

  System:
    OS: Linux 5.15 Ubuntu 20.04 LTS (Focal Fossa)
    CPU: (20) x64 AMD Ryzen 9 7950X 16-Core Processor
    Memory: 27.62 GB / 31.21 GB
  Binaries:
    Node: 18.15.0 - ~/.nvm/versions/node/v18.15.0/bin/node
    Yarn: 3.5.0 - ~/.yarn/bin/yarn
    npm: 9.5.0 - ~/.nvm/versions/node/v18.15.0/bin/npm
  Monorepos:
    Yarn Workspaces: 3.5.0
  Packages:
    babel-loader: 9.1.2 => 9.1.2 
    webpack: 5.77.0 => 5.77.0 
    webpack-cli: 5.0.1 => 5.0.1 
    webpack-dev-server: 4.13.2 => 4.13.2 

[alexander-akait]

Please update to https://github.com/webpack-contrib/postcss-loader/releases/tag/v7.2.1

[ntucker]

@alexander-akait 7.2.1 is the version this broke in. Previous versions work fine. You can even see that in 7.1 the problem package cosmiconfig-typescript-loader is not included https://github.com/webpack-contrib/postcss-loader/blob/v7.1.0/package.json#L44

[alexander-akait]

I can't reproduce, check your version again

[alexander-akait]

You can check our code https://github.com/webpack-contrib/postcss-loader/blob/master/src/utils.js#L52

[ntucker]

See https://yarnpkg.com/features/pnp if you don't specify the dependency, yarn will not find it because its resolution is ambiguous. If you want this to be optional you must specify it as an optional peerdependency

https://github.com/webpack-contrib/postcss-loader/blob/master/src/utils.js#L56 this line should not be executed unless the dependency is listed in the package executing it. Simply adding this as a peerDep solves this problem.

I'm happy to make a PR if you're unsure how to do this.

[alexander-akait]

Sorry I don't undestand you, we don't use ts-node and other things directly? Why we should add them?

[ntucker]

• you use it right here
• ts-node is listed as a peerDependency of cosmiconfig-typescript-loader, therefore you must add it so it can be resolved correctly

Even in loose mode of yarn it will warn you about these bugs

[alexander-akait]

PR welcome, not sure how we can fix it here, because it is an optinal dependecy, so we can't list it in dependecies

[alexander-akait]

https://github.com/Codex-/cosmiconfig-typescript-loader/issues/79

[alexander-akait]

Only one thing we can do - inline code of the typescript cosmiconfig loader and put everything in peer deps