Unable to resolve path to module 'katex' with eslint-import-resolver-webpack

[andersk]

import katex from "katex"; is valid according to both native Node.js and webpack. But eslint-import-resolver-webpack is unable to resolve it, leading to a spurious error Unable to resolve path to module 'katex'. This might have something to do with the exports map in katex/package.json.

Complete reproducible example:

src.js

import katex from "katex";
console.log("Hello KaTeX", katex.version);

.eslintrc.json

{
  "env": {
    "es6": true
  },
  "parserOptions": {
    "sourceType": "module"
  },
  "plugins": ["import"],
  "rules": {
    "import/no-unresolved": "error"
  },
  "settings": {
    "import/resolver": "webpack"
  }
}

package.json

{
  "type": "module",
  "dependencies": {
    "eslint": "8.1.0",
    "eslint-import-resolver-webpack": "0.13.2",
    "eslint-plugin-import": "2.25.2",
    "katex": "0.15.1",
    "webpack": "5.61.0",
    "webpack-cli": "4.9.1"
  }
}

$ npm i
…

$ node src.js
Hello KaTeX 0.15.1

$ npx webpack --mode=production
…
webpack 5.61.0 compiled with 3 warnings in 2988 ms

$ node dist/main.js 
Hello KaTeX 0.15.1

$ npx eslint src.js

/tmp/test/src.js
  1:19  error  Unable to resolve path to module 'katex'  import/no-unresolved

✖ 1 problem (1 error, 0 warnings)

[ljharb]

The issue is that katex has entry points defined in exports that do not, for backwards compatibility, have corresponding files on the filesystem for older nodes to resolve.

This package uses resolve, and neither has support yet for exports. So, either katex will have to add those files (which it should anyways, since it doesn't declare engines.node, which means it probably works on every node version), or, you'll need to use import/ignore on that dependency until we're able to add that support.