Jest should resolve its dependencies from its own location rather than rootDir

Create React App users bumped into this issue recently. A third party package started depending on jest-validate, and that caused npm to hoist jest-environment-node to the top of the app tree. Unfortunately, Jest resolves environment package from the project root instead of from its own Node module location so as a result, it loads the wrong (hoisted) jest-environment-node.

I think the jest package should resolve any own dependencies from its own location (just like Node resolution works) rather than from the project root folder.

[SimenB]

Nice detective work, this is indeed a subtle and annoying bug.

I think it makes sense to special case (jest-environment-)node and (jest-environment-)jsdom and skip the Resolver.findNodeModule stuff for them.

[dspacejs]

Running into this issue and not sure how to solve it. Anyone know what to do?

I’ve installed redux-actions, which has its own reduce-reducers dependency. Now after installing reduce-reducers for my project, it’s causing errors (because redux-actions expects reduce-reducers to be a different version).

This works fine in my app and is therefore set up correctly, it’s just that the Jest tests are now failing because Jest is loading the wrong version.

For now I’ve just installed the version redux-actions expects as a workaround, but I think Jest should handle module resolution the same way Node does.