feat(nuxt): expose getIslandHash + hashKey + improve hash for keys

[danielroe]

🔗 Linked issue

resolves #34236 (comment)

📚 Description

two things:

1. this exposes a hash function for libraries like nuxt-og-image to allow nuxt to tweak or change our algorithm for computing island hashes without inadvertently breaking everyone
2. it also swaps out the implementation for computing keys for useFetch/useAsyncData with a smaller, faster one based on object-identity and fnv1a-64 (a tiny implementation of fnv-1a optimised for keys like this)

note that we don't see a bundle size improvement for (2) because we still use ohash for island keys, to avoid breaking anyone relying on the current implementation

[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	fnv1a-64@​0.1.1
	object-identity@​0.2.3

View full report

[pkg-pr-new]

Open in StackBlitz

@nuxt/kit

npm i https://pkg.pr.new/@nuxt/kit@35583

@nuxt/nitro-server

npm i https://pkg.pr.new/@nuxt/nitro-server@35583

nuxt

npm i https://pkg.pr.new/nuxt@35583

@nuxt/rspack-builder

npm i https://pkg.pr.new/@nuxt/rspack-builder@35583

@nuxt/schema

npm i https://pkg.pr.new/@nuxt/schema@35583

@nuxt/vite-builder

npm i https://pkg.pr.new/@nuxt/vite-builder@35583

@nuxt/webpack-builder

npm i https://pkg.pr.new/@nuxt/webpack-builder@35583

commit: 01ee2f6

[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@packages/nitro-server/src/runtime/handlers/island.ts`:
- Line 174: Remote island hash generation is inconsistent between server and
client. In packages/nitro-server/src/runtime/handlers/island.ts:174, update
expectedHash in the island handler to exclude source; in
packages/nuxt/src/app/components/nuxt-island.ts:108, remove source from the
client hashId inputs and incorporate it into the nuxtApp.payload.data cache key
instead, using a local fallback so identical islands from different sources do
not collide.

In `@packages/nuxt/src/app/composables/fetch.ts`:
- Around line 91-93: Update the plain-object branch in the fetch composable to
pass the already-unwrapped value directly to hashKey, removing the unnecessary
reactive wrapper while preserving the existing segment generation behavior.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 542ef458-16ca-4512-9025-b8da739e8025

📥 Commits

Reviewing files that changed from the base of the PR and between 58223f1 and e864260.

⛔ Files ignored due to path filters (2)

• packages/nuxt/package.json is excluded by !**/package.json
• pnpm-lock.yaml is excluded by !**/pnpm-lock.yaml, !pnpm-lock.yaml

📒 Files selected for processing (12)

• packages/nitro-server/src/runtime/handlers/island.ts
• packages/nuxt/meta.js
• packages/nuxt/src/app/components/nuxt-island.ts
• packages/nuxt/src/app/composables/asyncData.ts
• packages/nuxt/src/app/composables/component.ts
• packages/nuxt/src/app/composables/fetch.ts
• packages/nuxt/src/app/composables/hash.ts
• packages/nuxt/src/app/index.ts
• packages/nuxt/src/app/island-hash.ts
• packages/nuxt/test/hash.test.ts
• packages/nuxt/test/island-hash.test.ts
• pnpm-workspace.yaml

[codspeed-hq]

Merging this PR will improve performance by 16.39%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
✅ 20 untouched benchmarks
⏩ 3 skipped benchmarks¹

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	loadNuxt in the basic test fixture (dev)	374.5 ms	321.7 ms	+16.39%

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing feat/hash-function (01ee2f6) with main (a5c1086)}

Footnotes

1. 3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@packages/nuxt/src/app/utils/hash.ts`:
- Around line 29-30: Update the native-function detection in the hash utility
around Function.prototype.toString.call(fn) to use a whitespace-tolerant regular
expression instead of the exact endsWith('[native code] }') check. Preserve the
existing native source formatting and fallback behavior while allowing
browser-specific newlines and spacing.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 04efe375-d3bd-4653-80f1-9e08737718e2

📥 Commits

Reviewing files that changed from the base of the PR and between a3d80c0 and ecbe529.

⛔ Files ignored due to path filters (1)

• pnpm-lock.yaml is excluded by !**/pnpm-lock.yaml, !pnpm-lock.yaml

📒 Files selected for processing (6)

• packages/nuxt/src/app/composables/asyncData.ts
• packages/nuxt/src/app/composables/component.ts
• packages/nuxt/src/app/composables/fetch.ts
• packages/nuxt/src/app/index.ts
• packages/nuxt/src/app/utils/hash.ts
• packages/nuxt/test/hash.test.ts

🚧 Files skipped from review as they are similar to previous changes (5)

• packages/nuxt/test/hash.test.ts
• packages/nuxt/src/app/composables/component.ts
• packages/nuxt/src/app/composables/asyncData.ts
• packages/nuxt/src/app/composables/fetch.ts
• packages/nuxt/src/app/index.ts

[cernymatej]

❤️

[harlan-zw]

Yess, thank you 🙏