babel 7 inconsistent transformation

[chrisblossom]

🐛 Bug Report

When upgrading to babel 7 some files are not being transformed. I have both babel-core@7.0.0-bridge.0 and babel-jest installed.

Example error message:

To Reproduce

https://github.com/chrisblossom/backtrack/tree/babel-7

git clone https://github.com/chrisblossom/backtrack.git
cd backtrack
git checkout babel-7
npm install
npm run test

jest --clearCache sometimes helps some tests pass.

Expected behavior

All tests pass.

Link to repl or repo (highly encouraged)

https://github.com/chrisblossom/backtrack/tree/babel-7
chrisblossom/backtrack@697617c

Run npx envinfo --preset jest

  System:
    OS: macOS High Sierra 10.13.6
    CPU: x64 Intel(R) Core(TM) i9-8950HK CPU @ 2.90GHz
  Binaries:
    Node: 8.11.4 - ~/.nvm/versions/node/v8.11.4/bin/node
    Yarn: 1.9.4 - /usr/local/bin/yarn
    npm: 6.4.1 - ~/.nvm/versions/node/v8.11.4/bin/npm
  npmPackages:
    jest: ^23.6.0 => 23.6.0

[ahrbil]

I have the same issue

[milesj]

Try using babel.config.js at the root.

Also, what is the output of npm ls babel-core?

[ahrbil]

running npm ls babel-core returns empty
I have my babel.config.js at the root
I followed the instructions on jest website about getting jest and babel 7 work but still I can't get import statement work on my tests I get the same error as @chrisblossom
instead using require all tests pass

[milesj]

npm ls babel-core shouldn't return empty if you have it as an explicit dep. Are you using yarn instead?

[ahrbil]

yes I use yarn but same error

[milesj]

In yarn it's yarn why babel-core.

[ahrbil]

now I get this instead of empty

yarn why v1.7.0
[1/4] Why do we have the module "babel-core"...?
[2/4] Initialising dependency graph...
[3/4] Finding dependency...
[4/4] Calculating file sizes...
=> Found "babel-core@7.0.0-bridge.0"
info Has been hoisted to "babel-core"
info This module exists because it's specified in "devDependencies".
info Disk size without dependencies: "2.5KB"
info Disk size with unique dependencies: "2.5KB"
info Disk size with transitive dependencies: "2.5KB"
info Number of shared dependencies: 0
=> Found "jest-config#babel-core@6.26.3"
info This module exists because "jest#jest-cli#jest-config" depends on it.
info Disk size without dependencies: "118KB"
info Disk size with unique dependencies: "118KB"
info Disk size with transitive dependencies: "118KB"
info Number of shared dependencies: 41
=> Found "jest-runtime#babel-core@6.26.3"
info This module exists because "jest#jest-cli#jest-runtime" depends on it.
info Disk size without dependencies: "118KB"
info Disk size with unique dependencies: "3.92MB"
info Disk size with transitive dependencies: "118KB"
info Number of shared dependencies: 41
=> Found "babel-register#babel-core@6.26.3"
info This module exists because "jest#jest-cli#jest-runtime#babel-core#babel-register" depends on it.
info Disk size without dependencies: "118KB"
info Disk size with unique dependencies: "3.92MB"
info Disk size with transitive dependencies: "7.03MB"
info Number of shared dependencies: 41

[glebcha]

Faced exactly the same jest behaviour. Using pure babel-jest or calling createTramsformer with custom config. 20% of tests passed fine while others got undefined options argument in createTransformer.

[michaloo]

I think the problem is that babel-jest expects babel configuration file babel.config.js to simply return a JS object:

https://github.com/facebook/jest/blob/master/packages/babel-jest/src/index.js#L58

while babel js started to promote a config API which allows to return a function:

https://babeljs.io/docs/en/config-files#config-function-api

and this is what we have in the example repo project:

https://github.com/chrisblossom/backtrack/blob/babel-7/.babelrc.js

[valerie1995]

You 9and

…

On Tue, Oct 16, 2018, 1:20 AM Michał Rączka ***@***.***> wrote: I think the problem is that babel-jest expects babel configuration file babel.config.js to simply return a JS object: https://github.com/facebook/jest/blob/master/packages/babel-jest/src/index.js#L58 while babel js started to promote a config API which allows to return a function: https://babeljs.io/docs/en/config-files#config-function-api and this is what we have in the example repo project: https://github.com/chrisblossom/backtrack/blob/babel-7/.babelrc.js — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#7021 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AZUzB9euVR-AG7jJmhPoeWSLmuoEmoC0ks5ulZbYgaJpZM4W013K> .

[jahed]

I "fixed" this on my end. In that, I deleted a bunch of stuff that I didn't see a need for -- likely due to my own ignorance. Of course, a proper fix would be nice, but this has worked fine for me so far.

Essentially, hand over Babel's config resolution to Babel and don't try to manually resolve it on Jest's end.

https://github.com/jahed/jest/commit/42075095732f35a5c02a3eb1c36df671a4eb0071

[jahed]

I've found a better temporary solution to this problem. Install babel-core bridge. Instructions here:

https://github.com/babel/babel-bridge

[chrisblossom]

Has anyone found a fix for this? I still am unable to get jest to work with babel 7.

I've tried using babel.config.js and here is the output of npm ls babel-core:

➜ npm ls babel-core
@backtrack/core@0.1.22 /Users/chris/github/backtrack/core
├── babel-core@7.0.0-bridge.0
└─┬ jest@23.6.0
  └─┬ jest-cli@23.6.0
    ├─┬ jest-config@23.6.0
    │ └─┬ babel-core@6.26.3
    │   └─┬ babel-register@6.26.0
    │     └── babel-core@6.26.3
    └─┬ jest-runtime@23.6.0
      └── babel-core@6.26.3

[airato]

@chrisblossom if you change the way how the module is being required here https://github.com/chrisblossom/backtrack/blob/697617c7f499c2c8e4c0dd2b7056c1d070a10fcf/src/stats-file/load-stats-file.test.js#L5
from

const loadStatsFile = () => require('./load-stats-file').loadStatsFile();

to

const loadStatsFile = require('./load-stats-file').loadStatsFile;

and run that test npm test -- --no-cache src/stats-file/load-stats-file.test.js
it would not complain about unknown syntax

Seems like something weird is going on with lazy require...

[chrisblossom]

@airato thanks for the reply! Interestingly enough I just came to the same conclusion trying to move to Typescript.

I use the lazy require in combination with resetModules to ensure tests are sandboxed. I'll see if it causes me any issues trying to remove the lazy require.

[chrisblossom]

Closing this in favor of #7438.

[github-actions]

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