Fork-ts-checker-webpack-plugin: Could not find a declaration file for module 'eslint'

[StefanoMagrassi]

Current behavior

My Webpack config file is written in TS and type-checked on test/release.

With v4 of fork-ts-checker-webpack-plugin tsc started to complain about a not found declaration file for eslint

node_modules/fork-ts-checker-webpack-plugin/lib/issue/eslint/EsLintIssueFactory.d.ts:1:25 - error TS7016: Could not find a declaration file for module 'eslint'. '/MY_PROJECT_DIR/node_modules/eslint/lib/api.js' implicitly has an 'any' type.
  Try `npm install @types/eslint` if it exists or add a new declaration (.d.ts) file containing `declare module 'eslint';`

1 import * as eslint from 'eslint';
                          ~~~~~~~~

node_modules/fork-ts-checker-webpack-plugin/lib/issue/eslint/FileAwareEsLintMessage.d.ts:1:25 - error TS7016: Could not find a declaration file for module 'eslint'. '/MY_PROJECT_DIR/node_modules/eslint/lib/api.js' implicitly has an 'any' type.
  Try `npm install @types/eslint` if it exists or add a new declaration (.d.ts) file containing `declare module 'eslint';`

1 import * as eslint from 'eslint';

Expected behavior

type-checking should pass

Steps to reproduce the issue

tsconfig.json

{
  "compilerOptions": {
    "noEmit": true,
    "target": "es5",
    "module": "commonjs",
    "esModuleInterop": true,
    "lib": ["es6", "dom", "es2016.array.include"],
    "importHelpers": true,
    "sourceMap": true,
    "outDir": "./dist",
    "jsx": "preserve",
    "alwaysStrict": true,
    "strict": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "forceConsistentCasingInFileNames": true,
    "types": ["node", "jest", "jest-enzyme"],
    "typeRoots": ["./typings", "./node_modules/@types"],
    "baseUrl": ".",
    "paths": {
      "*": ["*", "typings/*"]
    }
  },
  "include": [
    "./src",
    "./scripts",
    "./config",
    "./webpack.config.ts",
    "./typings"
  ]
}

webpack.config.ts

import ForkTsCheckerWebpackPlugin from 'fork-ts-checker-webpack-plugin';

export = {
  // ... various webpack configuration

 plugins: [
  new ForkTsCheckerWebpackPlugin()
 ]
}

and then run

npx tsc

Environment

• fork-ts-checker-webpack-plugin: 4.0.1
• typescript: 3.7.5
• tslint
• eslint: 6.8.0
• webpack: 4.41.5
• os: Ubuntu 18.04

[johnnyreilly]

Thanks for the report. @piotr-oles how do you want to proceed with this? I'd suggest we don't want to make @types/eslint a dependency.

I suspect this is a side effect of moving to use import * as eslint from 'eslint'; style imports rather than targeted ones that only import the types being used.

If so, this could probably be fixed by switching back to the import { TYPE } from 'eslint'; style imports

[piotr-oles]

Thanks @StefanoMagrassi , I'm working on the fix.

You are right @johnnyreilly , I will remove @types/eslint dependency to forbid using types from eslint. The PR will be soon 👍

[piotr-oles]

:tada: This issue has been resolved in version 4.0.2 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: