Failed to load plugin 'jest' declared in 'BaseConfig': Cannot find module 'eslint-plugin-jest'

[mishabruml]

Thanks for an awesome project! Having issues with jest eslint plugin:

xo-config.json:

{
  "rules": {
    "object-curly-spacing": ["error", "always"],
    "@typescript-eslint/object-curly-spacing": ["error", "always"]
  },
  "plugins": ["jest"],
  "extends": ["plugin:jest/recommended"]
}

package.json:

{
  "name": "ts-node-starter",
  "engines": {
    "node": "^14.18.0",
    "npm": "^6.14.15"
  },
  "version": "1.0.0",
  "description": "typescript node project boilerplate",
  "author": "Misha Bruml",
  "license": "ISC",
  "type": "module",
  "scripts": {
    "tsc:check": "tsc --noEmit",
    "lint": "npm run tsc:check && xo",
    "test": "jest"
  },
  "devDependencies": {
    "@types/jest": "^26.0.24",
    "@types/node": "^14.17.20",
    "eslint-plugin-jest": "^24.5.0",
    "jest": "^27.2.4",
    "ts-jest": "^27.0.5",
    "ts-node": "^9.1.1",
    "typescript": "^4.4.3",
    "xo": "^0.45.0"
  },
  "dependencies": {}
}

Is this a problem with the vscode plugin? Running npx xo works fine, and changing a file to purposefully break a jest rule yields e.g:

test/hello-world/index.test.ts:6:7
  ✖  6:7  Unexpected focused test.  jest/no-focused-tests

  1 error

[mishabruml]

i resolved this issue by restarting my laptop, rm -rf node_modules && npm i and restarting VS Code. Not sure which of those was the one that actually was effective 🤷

[Primajin]

Hmm I am running into the same issue but on CLI - what I don't really get is that it is crashing in @typescript-eslint though I don't even use Typescript.

> eyesbound@3.0.0 xo
> xo --fix

TypeError: Failed to load plugin 'jest' declared in 'BaseConfig': Class extends value undefined is not a constructor or null
Referenced from: BaseConfig
    at Object.<anonymous> (R:\eyesbound\node_modules\@typescript-eslint\experimental-utils\dist\ts-eslint\CLIEngine.js:12:34)
    at Module._compile (node:internal/modules/cjs/loader:1097:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1149:10)
    at Module.load (node:internal/modules/cjs/loader:975:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Module.require (node:internal/modules/cjs/loader:999:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object.<anonymous> (R:\eyesbound\node_modules\@typescript-eslint\experimental-utils\dist\ts-eslint\index.js:14:14)
    at Module._compile (node:internal/modules/cjs/loader:1097:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1149:10)

[Primajin]

OK I found the issue - when installing eslint-plugin-jest I falsely ran:

npm i --save-dev eslint eslint-plugin-jest

this bumped eslint to 8.3.0 and apparently >v.8 is not yet usable with all of the plugins eslint/eslint#15149

[CaswellRyder]

Theres also an issue where VS code bugs out and omits the eslint plugin and restarting VS Code for me worked.
@mishabruml