perf(oxfmt): Use `worker_threads` by `tinypool` for prettier formatting by leaysgur · Pull Request #16618 · oxc-project/oxc

leaysgur · 2025-12-09T01:05:38Z

Part of #16606

Use worker_threads via tinypool lib
- Until now, the Rust side had been operating entirely in a multithreaded manner, while the JS side remained single-threaded, resulting in sequential execution and waiting
- Number of threads are the same value for Rust side
Also can be applied to embedded formatting path
Since tinypool couldn't be bundled, defined as dependencies in the npm/oxfmt/package.json

leaysgur · 2025-12-09T01:05:57Z

perf(oxfmt): Use worker_threads by tinypool for prettier formatting #16618 👈 (View in Graphite)
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apps/oxfmt/src-js/prettier-worker.ts

Copilot

Pull request overview

This PR refactors oxfmt to use worker threads for Prettier formatting via the tinypool library, enabling parallel execution on the JavaScript side to match the Rust side's multi-threaded architecture. Previously, while Rust operated in a multithreaded manner, the JS side remained single-threaded, causing sequential execution bottlenecks.

Key Changes:

Adds tinypool dependency for worker thread pool management
Updates setupConfig callback to accept numThreads parameter matching Rayon's thread count
Splits Prettier logic into worker (prettier-worker.ts) and proxy (prettier-proxy.ts) files

Reviewed changes

Copilot reviewed 8 out of 10 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
`pnpm-lock.yaml`	Adds tinypool 2.0.0 to lockfile for both app and npm package
`npm/oxfmt/package.json`	Declares tinypool as production dependency
`apps/oxfmt/tsdown.config.ts`	Adds worker entry point and documents why tinypool cannot be bundled
`apps/oxfmt/src/main_napi.rs`	Updates TypeScript type annotation for setupConfigCb to include numThreads parameter
`apps/oxfmt/src/core/external_formatter.rs`	Updates callback signatures to pass num_threads to JavaScript side
`apps/oxfmt/src/cli/format.rs`	Passes thread count to external formatter setup before creating SourceFormatter
`apps/oxfmt/src-js/prettier-worker.ts`	New worker implementation that receives config via workerData and formats code in parallel
`apps/oxfmt/src-js/prettier-proxy.ts`	Refactored to create worker pool and dispatch formatting tasks to workers
`apps/oxfmt/src-js/bindings.d.ts`	Updates TypeScript signature for format function to reflect numThreads parameter
`apps/oxfmt/package.json`	Adds tinypool dependency for development builds

Files not reviewed (1)

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apps/oxfmt/src/core/external_formatter.rs

apps/oxfmt/src-js/prettier-worker.ts

apps/oxfmt/src-js/prettier-proxy.ts

apps/oxfmt/src-js/prettier-worker.ts

apps/oxfmt/tsdown.config.ts

Dunqing

Overall, it looks good! Just one thing that I do not know if it will work. Feel free to do it in the follow-up PR if you want.

apps/oxfmt/src-js/prettier-worker.ts

Dunqing

Great!

Dunqing · 2025-12-09T04:18:52Z

Merge activity

Dec 9, 4:18 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Dec 9, 4:18 AM UTC: Dunqing added this pull request to the Graphite merge queue.
Dec 9, 4:24 AM UTC: The Graphite merge queue couldn't merge this PR because it was not satisfying all requirements (Failed CI: 'Test NAPI').
Dec 9, 4:38 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Dec 9, 4:38 AM UTC: leaysgur added this pull request to the Graphite merge queue.
Dec 9, 4:39 AM UTC: Merged by the Graphite merge queue.

…ng (#16618) Part of #16606 - Use `worker_threads` via `tinypool` lib - Until now, the Rust side had been operating entirely in a multithreaded manner, while the JS side remained single-threaded, resulting in sequential execution and waiting - Number of threads are the same value for Rust side - Also can be applied to embedded formatting path - Since `tinypool` couldn't be bundled, defined as `dependencies` in the `npm/oxfmt/package.json`

…ng (oxc-project#16618) Part of oxc-project#16606 - Use `worker_threads` via `tinypool` lib - Until now, the Rust side had been operating entirely in a multithreaded manner, while the JS side remained single-threaded, resulting in sequential execution and waiting - Number of threads are the same value for Rust side - Also can be applied to embedded formatting path - Since `tinypool` couldn't be bundled, defined as `dependencies` in the `npm/oxfmt/package.json`

github-actions bot added A-cli Area - CLI A-formatter Area - Formatter C-cleanup Category - technical debt or refactoring. Solution not expected to change behavior labels Dec 9, 2025

leaysgur mentioned this pull request Dec 9, 2025

oxfmt: super slow while formatting non-js files #16606

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leaysgur force-pushed the 12-09-refactor_oxfmt_use_worker_threads_by_tinypool_for_formatfile_ branch from 106ee0d to 602ccaf Compare December 9, 2025 01:12

Boshen approved these changes Dec 9, 2025

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leaysgur force-pushed the 12-09-refactor_oxfmt_use_worker_threads_by_tinypool_for_formatfile_ branch 7 times, most recently from 9938678 to 67808c2 Compare December 9, 2025 03:06

leaysgur changed the title ~~refactor(oxfmt): Use worker_threads by tinypool for formatFile()~~ refactor(oxfmt): Use worker_threads by tinypool for prettier formatting Dec 9, 2025

leaysgur force-pushed the 12-09-refactor_oxfmt_use_worker_threads_by_tinypool_for_formatfile_ branch 2 times, most recently from 243ce15 to 9737454 Compare December 9, 2025 03:32

leaysgur marked this pull request as ready for review December 9, 2025 03:38

Copilot AI review requested due to automatic review settings December 9, 2025 03:38

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Boshen changed the title ~~refactor(oxfmt): Use worker_threads by tinypool for prettier formatting~~ perf(oxfmt): Use worker_threads by tinypool for prettier formatting Dec 9, 2025

github-actions bot added the C-performance Category - Solution not expected to change functional behavior, only performance label Dec 9, 2025

Boshen approved these changes Dec 9, 2025

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leaysgur force-pushed the 12-09-refactor_oxfmt_use_worker_threads_by_tinypool_for_formatfile_ branch from 9737454 to c5885c5 Compare December 9, 2025 03:51

Dunqing requested changes Dec 9, 2025

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leaysgur requested a review from Dunqing December 9, 2025 03:52

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leaysgur force-pushed the 12-09-refactor_oxfmt_use_worker_threads_by_tinypool_for_formatfile_ branch from c5885c5 to c9770b9 Compare December 9, 2025 03:58

Dunqing approved these changes Dec 9, 2025

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Dunqing added the 0-merge Merge with Graphite Merge Queue label Dec 9, 2025

graphite-app bot force-pushed the 12-09-refactor_oxfmt_use_worker_threads_by_tinypool_for_formatfile_ branch from c9770b9 to 6f3aaba Compare December 9, 2025 04:19

graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Dec 9, 2025

leaysgur added the 0-merge Merge with Graphite Merge Queue label Dec 9, 2025

graphite-app bot merged commit 6f3aaba into main Dec 9, 2025
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graphite-app bot deleted the 12-09-refactor_oxfmt_use_worker_threads_by_tinypool_for_formatfile_ branch December 9, 2025 04:39

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Boshen mentioned this pull request Dec 15, 2025

release(apps): oxlint v1.33.0 && oxfmt v0.18.0 #16888

Merged

morlay mentioned this pull request Dec 22, 2025

Segfault and DataCloneError with worker threads in oxfmt on Bun 1.3.5 oven-sh/bun#25610

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perf(oxfmt): Use `worker_threads` by `tinypool` for prettier formatting#16618

perf(oxfmt): Use `worker_threads` by `tinypool` for prettier formatting#16618
graphite-app[bot] merged 1 commit intomainfrom
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leaysgur commented Dec 9, 2025 •

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leaysgur commented Dec 9, 2025 •

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Dunqing commented Dec 9, 2025 •

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