ts-jest ignores injectGlobals and leaks @types/jest into all files

[biro456]

🐛 Bug Report

I'm writing TypeScript code and I want to use jest with injectGlobals turned off, direclty importing from @jest/global. But when using ts-jest all globals end up being available in the global context anyway.

That makes auto-complete suggest the global version and makes it possible compile any code in the project with the the globals.

Step to Reproduce

https://gist.github.com/biro456/40501e3bc024ba92cd3113a7e99d5ebe

1. Install dependencies
2. Run build script
3. Run node sample.js
4. Run script test

TypeScript will compile without errors but sample.js will throw a ReferenceError when executed.
Tests will not error though, which means injectGlobals is being ignored.

Expected behaviour

TypeScript should error when a Jest global is used in any file.

envinfo

System:
    OS: Ubuntu 20.04.2 LTS on WSL 2 on Windows 10 Pro 20H2 19042.804
    Node version.: 14.15.4

Npm packages:
    jest: 26.6.3
    ts-jest: 26.5.2
    typescript: 4.1.5

The solution would be to remove @types/jest from dependencies, allowing package users to import it only if necessary, and change ts-jest to respect injectGlobals.

I saw that it was #1859 that moved @types/jest to dependencies, so an alternative solution would be needed to avoid breaking Yarn 2 again.

[ahnpnl]

Duplicate with #2406

I think the best is just removing @types/jest from dependencies. Actually yarn 2 doesn't break but it just complains about the dep, the test still runs fine so I think that is fine for now.

The plan to move mocked util function to jest might take time.

[ahnpnl]

Regarding to injectGlobals, ts-jest can't do anything about this option. ts-jest only transforms ts to js so it doesn't know what injectGlobals is

[biro456]

I'll check on jest to see if injectGlobals is broken over there then.

[ahnpnl]

if you use jest@next and ts-jest@next, it will work. Note that injectGlobals: false only works with jest-circus. These are the steps:

• Upgrade to jest@next and ts-jest@next
• Delete @types/jest in node_modules
• Add import { describe, it, expect } from '@jest/globals' to your sample.spec.ts
• Clear jest cache
• Run test again and test will pass

[ahnpnl]

For jest@latest and ts-jest@latest, you will need to add testRunner: 'jest-circus' to your jest config but I can't make it work, it is not like next tag not sure why.

[biro456]

I'm already using jest-circus and @jest/global on the actual repository I was working on.
But thanks!