Fix/babel plugin emotion function object crash

[kddc]

What:
Fix the babel plugin crashing when facing objects with multiple emotion classes where some of them are arrow functions and adding the correct labels to the classes.

Why:
We have something like this in our code

const { useStyles } = {
  useStyles: () => {
    return {
      color: css`
        color: hotpink;
      `,
      colorFn: () => css`
        color: hotpink;
      `,
    }
  }
}

When the babel plugin processes the arrow function inside of it, it crashes with TypeError: Cannot read properties of undefined (reading 'charAt'), as it can not find a declaratorName for the function in the label.js file.

How:
The getDeclaratorName method checked for parents that could be of type ArrowFunctionExpression, but this was not handled inside the body of this function. I check the parents parent in this case using the existing getDeclaratorName method.

Checklist:

• Documentation
• Tests
• Code complete
• Changeset

[changeset-bot]

🦋 Changeset detected

Latest commit: cd6bb15

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@emotion/babel-plugin	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit cd6bb15:

Sandbox	Source
Emotion	Configuration

[codecov]

Codecov Report

Merging #2585 (cd6bb15) into main (169ac54) will decrease coverage by 0.03%.
The diff coverage is 100.00%.

Impacted Files	Coverage Δ
packages/babel-plugin/src/utils/label.js	92.78% <100.00%> (-0.63%)	⬇️
packages/babel-plugin/src/styled-macro.js	98.00% <0.00%> (-0.12%)	⬇️

[Andarist]

@kddc this was the more appropriate fix. The isArrowFunctionExpression block that you have introduced has covered the introduced test case but I believe that it was more about improving label extraction for this specific case than about fixing a crash (the latter was a byproduct of the former though, in that scenario).

By patching the underlying issue here I've managed to also fixed the weird test case introduced as no-label-obj-pattern-computed-property

[kddc]

@Andarist Awesome - that's even better then :)

[Andarist]

@kddc thank you very much for the PR! this means a lot ❤️