fix: treat wrap={undefined} like an omitted wrap prop

[EvHaus]

Summary

Similar to #3149 and #3142, this fixes a regression from the layout TypeScript conversion.

After that change, an explicit wrap={undefined} was treated as falsy (no wrapping), while an omitted wrap prop still defaulted to true. Those should behave the same.

Behaviour

Usage	Result
<View />	true
<View wrap={undefined} />	true
<View wrap={null} />	false
<View wrap={false} />	false
<View wrap={true} />	true

null stays falsy (disables wrapping). Only undefined / omitted use the default.

Also adds unit tests for getWrap.

Test plan

• yarn vitest run packages/layout/tests/node/getWrap.test.ts
• Confirm wrapping still works for views with no wrap prop
• Confirm wrap={false} still prevents page breaks inside the view

[changeset-bot]

🦋 Changeset detected

Latest commit: 276b6bf

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

This PR includes changesets to release 7 packages

Name	Type
@react-pdf/layout	Patch
@react-pdf/renderer	Patch
@react-pdf/math	Patch
@react-pdf/mermaid	Patch
next-14	Patch
next-15	Patch
@react-pdf/vite-example	Patch

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[diegomura]

Is it correct that undefined was already returning true? I'm not sure about null though. That's a falsy value. Makes more sense to me to false for null than true

[EvHaus]

Is it correct that undefined was already returning true?

The current behaviour is:

1. <View /> is treated as true
2. <View wrap={undefined} /> is treated as false
3. <View wrap={null} /> is treated as false
4. <View wrap={false} /> is treated as false
5. <View wrap={true} /> is treated as true

I think 1, 4 and 5 make sense. But 2 and 3 are unexpected to me.

I'm not sure about null though. That's a falsy value. Makes more sense to me to false for null than true

I see where you're coming from however given that "no value" (case 1) and undefined (case 2) will evaluate to true I think having null evaluate to true is a more developer-friendly/consistent experience.

Let me know if you feel strongly about it and I'll make the PR change accordingly. Thanks @diegomura!

[diegomura]

is treated as false

I don't think this is right. This case is treated as true. I believe that's a typo?

But 2 and 3 are unexpected to me.

null and undefined are falsy values. It doesn't make sense to me to be treated as true.

[EvHaus]

My bad on the typo. Updated comment and PR description. Kept null handling as falsy. However, I would still argue undefined should be handled as true. Otherwise you end up with:

• <View /> treated as true
• <View wrap={undefined} /> treated as false

Which I think is really unexpected/clumbsy behaviour. If you still disagree, feel free to close the PR.