fix(carbon-ads): keep the script id resolvable after unmount

[harlan-zw]

📚 Description

Unmounting ScriptCarbonAds crashes the page. carbon.js resolves #_carbonads_js from its own pending ad callback and reads .src off it with no null check, so removing that element throws inside third-party code where nothing can catch it. Sites that key the ad on the route to refresh it per page hit this on every navigation.

The root ref was also seeded from document.getElementById('_carbonads_js'), which is the script's id rather than a container. Every other registry component starts that ref at null.

Open question: two instances mounted at once still collide on the hardcoded id. Carbon's own code assumes one per page, so I left it alone.

🤖 AI disclosure: Harlan Agent Kit modified this description. My AI open-source policy.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
scripts-playground	Ready	Preview	Aug 20, 2026 3:15am

[harlan-zw]

Checked in a real browser against live carbon.js, since CI has no Carbon coverage.

Mount, unmount, remount, then three :key cycles on a page that mirrors how unlighthouse.dev uses the component:

Without this change, after unmount:
0 elements match #_carbonads_js
window._carbonads.getUrlVar('serve') -> TypeError: Cannot read properties of null (reading 'src')

With it, after unmount:
1 element matches #_carbonads_js
window._carbonads.getUrlVar('serve') -> 'CW7DTKJL'

Remount and the three key cycles kept exactly one script element and one rendered ad, with no page errors.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@nuxt/scripts@872

commit: 0d12693

[github-actions]

📦 Package Size

✅ No notable size changes

📚 22 runtime dependencies (no change)

All tracked output (27)

Package output	Gzipped	Raw
@nuxt/scripts-cli · runtime dependencies	72 kB	355 kB	✅
@nuxt/scripts-cli · dependency magicast	72 kB	355 kB	✅
@nuxt/scripts-cli · export .	3.4 kB	12 kB	✅
@nuxt/scripts-cli · published payload	3.4 kB	12 kB	✅
@nuxt/scripts · runtime dependencies	451 kB	2.00 MB	✅
@nuxt/scripts · dependency @nuxt/devtools-kit	2.9 kB	7.7 kB	✅
@nuxt/scripts · dependency @oxc-project/types	0 B	0 B	✅
@nuxt/scripts · dependency @vueuse/core	174 kB	707 kB	✅
@nuxt/scripts · dependency @vueuse/shared	39 kB	154 kB	✅
@nuxt/scripts · dependency h3	34 kB	146 kB	✅
@nuxt/scripts · dependency magic-string	9.4 kB	42 kB	✅
@nuxt/scripts · dependency oxc-walker	7.6 kB	31 kB	✅
@nuxt/scripts · dependency semver	25 kB	72 kB	✅
@nuxt/scripts · dependency sirv	8.8 kB	21 kB	✅
@nuxt/scripts · dependency unstorage	70 kB	225 kB	✅
@nuxt/scripts · dependency valibot	80 kB	592 kB	✅
@nuxt/scripts · dist/runtime	98 kB	284 kB	✅
@nuxt/scripts · export .	25 kB	105 kB	✅
@nuxt/scripts · export ./registry	28 kB	89 kB	✅
@nuxt/scripts · export ./stats	13 kB	89 kB	✅
@nuxt/scripts · export ./types-source	43 kB	222 kB	✅
@nuxt/scripts · published payload	208 kB	790 kB	✅
@nuxt/scripts · components runtime	2.4 kB	6.2 kB	✅
@nuxt/scripts · composables runtime	7.5 kB	24 kB	✅
@nuxt/scripts · registry runtime	42 kB	123 kB	✅
@nuxt/scripts · server runtime	28 kB	84 kB	✅
@nuxt/scripts · utils runtime	2.5 kB	7.4 kB	✅

Runtime dependencies (22)

Package	Dependency	Requested	Resolved	Cost
@nuxt/scripts-cli	magicast	^0.5.4	0.5.4	📦 72 kB gzip
@nuxt/scripts-cli	pathe	^2.0.3	2.0.3	♻️ free via Nuxt 4.5.1
@nuxt/scripts	@nuxt/devtools-kit	^3.4.1	3.4.1	📦 2.9 kB gzip
@nuxt/scripts	@oxc-project/types	^0.143.0	0.143.0	📦 0 B gzip
@nuxt/scripts	@vueuse/core	^14.4.0	14.4.0	📦 174 kB gzip
@nuxt/scripts	@vueuse/shared	^14.4.0	14.4.0	📦 39 kB gzip
@nuxt/scripts	consola	^3.4.2	3.4.2	♻️ free via Nuxt 4.5.1
@nuxt/scripts	defu	^6.1.7	6.1.7	♻️ free via Nuxt 4.5.1
@nuxt/scripts	h3	^1.15.11	1.15.11	📦 34 kB gzip
@nuxt/scripts	magic-string	^1.1.0	1.1.0	📦 9.4 kB gzip, Nuxt has 1.0.0
@nuxt/scripts	ofetch	^1.5.1	1.5.1	♻️ free via Nuxt 4.5.1
@nuxt/scripts	ohash	^2.0.11	2.0.11	♻️ free via Nuxt 4.5.1
@nuxt/scripts	oxc-walker	^1.1.1	1.1.1	📦 7.6 kB gzip, Nuxt has 1.0.0
@nuxt/scripts	pathe	^2.0.3	2.0.3	♻️ free via Nuxt 4.5.1
@nuxt/scripts	semver	^7.8.5	7.8.5	📦 25 kB gzip
@nuxt/scripts	sirv	^3.0.2	3.0.2	📦 8.8 kB gzip
@nuxt/scripts	std-env	^4.2.0	4.2.0	♻️ free via Nuxt 4.5.1
@nuxt/scripts	ufo	^1.6.4	1.6.4	♻️ free via Nuxt 4.5.1
@nuxt/scripts	ultrahtml	^1.7.0	1.7.0	♻️ free via Nuxt 4.5.1
@nuxt/scripts	unplugin	^3.3.0	3.3.0	♻️ free via Nuxt 4.5.1
@nuxt/scripts	unstorage	^1.17.5	1.17.5	📦 70 kB gzip
@nuxt/scripts	valibot	^1.4.2	1.4.2	📦 80 kB gzip

_{Baseline: main_@_a423e821___2026-08-20 · gzip is the comparison metric · changes below 16 B gzip are ignored}

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 205cde3a-7905-4205-bde8-8b3cdd244f37

📥 Commits

Reviewing files that changed from the base of the PR and between a423e82 and 0d12693.

📒 Files selected for processing (2)

• packages/script/src/runtime/components/ScriptCarbonAds.vue
• test/nuxt-runtime/script-component-lifecycle.nuxt.test.ts

Included review availability: Your plan provides up to 4 included reviews per hour; 3 remain after this review.

---

📝 Walkthrough

Walkthrough

The Carbon Ads component now initializes its element reference as null, removes an existing script before loading, and moves the loaded script to <head> during unmount. Lifecycle tests remove leftover scripts during cleanup, verify script persistence and placement data after unmount, and verify replacement when a new instance mounts.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 0d126

This localized lifecycle fix keeps the script reference resolvable after unmount and adds coverage for the behavior; no actionable merge-blocking risk remains after normal checks and review.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the Carbon Ads fix and states the main behavior change after unmount.
Description check	✅ Passed	The description explains the unmount crash, the root ref correction, the remaining ID collision, and the validation performed.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/carbon-ads-unmount-id

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}