Jest cannot use ts-jest when installed globally

🐛 Bug Report

I can run tests with a local install…

npm install --save-dev jest ts-jest typescript

But a global install causes this error when jest is executed:

● Validation Error:
  Module ts-jest in the transform option was not found.

(This occurs even if ts-jest, but not jest, is installed locally in the project.)

To Reproduce

• Run these terminal commands (including install of babel-core to avoid a “peer dependency” warning):

    mkdir temp
    cd temp
    npm init -f
    npm install --global jest ts-jest typescript babel-core
  

• Add package.json configuration for ts-jest:

  "jest": {
    "transform": {
      "^.+\\.tsx?$": "ts-jest"
    },
    "testRegex": "(/__tests__/.*|(\\.|/)(test|spec))\\.(jsx?|tsx?)$",
    "moduleFileExtensions": ["ts","tsx","js","jsx","json"]
  }
  

• Run jest to get “Module ts-jest in the transform option was not found.”

Expected behavior

If the error does not occur, the output is “No tests found”

Run npx envinfo --preset jest

npx: installed 1 in 2.921s

  System:
    OS: Windows 10
    CPU: x64 Intel(R) Core(TM) i5 CPU         750  @ 2.67GHz
  Binaries:
    npm: 6.1.0 - C:\Program Files\nodejs\npm.CMD

[chenop]

What solved for me was the path to babel-jest in the “transform” key inside the jest.config.js file -

transform: {
    "\\.js$": "../node_modules/babel-jest" 
}

Change it to:

transform: { . 
    "\\.js$": "<rootDir>/node_modules/babel-jest" // Use <rootDir> . 
 },  

[GeeWee]

Can you clarify @SimenB ? “Module ts-jest in the transform option was not found.” is definitely not an error that ts-jest is throwing. (I grepped our codebase to make sure) - are you sure this is not an error thrown by jest when it can’t find the specified preprocessor?