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perf(linter/plugins): replace arrays with Uint8Arrays#20190

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perf(linter/plugins): replace arrays with Uint8Arrays#20190
graphite-app[bot] merged 1 commit intomainfrom
om/03-09-perf_linter_plugins_replace_arrays_with_uint8array_s

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@overlookmotel overlookmotel commented Mar 10, 2026

Perf optimization to visitor compilation.

Replace 3 x Arrays with Uint8Arrays. These arrays only contain positive integers between 0 and 171, so Uint8Arrays are more suitable. Each entry takes 1 byte instead of 8 bytes, and the entries are strictly typed so should help V8 to optimize.

Resetting these arrays is also cheaper, and will never result in allocations, which the original Arrays likely did.

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overlookmotel commented Mar 10, 2026


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@github-actions github-actions bot added A-linter Area - Linter A-cli Area - CLI A-linter-plugins Area - Linter JS plugins C-performance Category - Solution not expected to change functional behavior, only performance labels Mar 10, 2026
@overlookmotel overlookmotel marked this pull request as ready for review March 10, 2026 10:56
@overlookmotel overlookmotel requested a review from camc314 as a code owner March 10, 2026 10:56
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Pull request overview

Optimizes oxlint’s JS-side visitor compilation by switching internal “active type id” tracking from dynamic number[] arrays to fixed-size Uint8Array views, reducing allocations and memory footprint in a hot path.

Changes:

  • Replaced 3 number[] “active type id” arrays with Uint8Arrays backed by a shared ArrayBuffer.
  • Switched iteration/reset logic to use explicit counters instead of mutating .length.
  • Added a debug assertion and clarified docs around the finalizeCompiledVisitorresetCompiledVisitor call ordering for non-leaf visitor cache safety.

@overlookmotel overlookmotel self-assigned this Mar 10, 2026
@overlookmotel overlookmotel force-pushed the om/03-09-perf_linter_plugins_pre-populate_cache_of_visitprop_objects branch from 095db8f to b2e9703 Compare March 10, 2026 11:24
@overlookmotel overlookmotel force-pushed the om/03-09-perf_linter_plugins_replace_arrays_with_uint8array_s branch from b0a93a6 to 576c42b Compare March 10, 2026 11:24
@overlookmotel overlookmotel added 0-merge Merge with Graphite Merge Queue labels Mar 10, 2026
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overlookmotel commented Mar 10, 2026

Merge activity

  • Mar 10, 11:47 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
  • Mar 10, 11:47 AM UTC: overlookmotel added this pull request to the Graphite merge queue.
  • Mar 10, 12:03 PM UTC: The Graphite merge queue couldn't merge this PR because it was not satisfying all requirements (Failed CI: 'Test NAPI').
  • Mar 10, 12:19 PM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
  • Mar 10, 12:31 PM UTC: overlookmotel added this pull request to the Graphite merge queue.
  • Mar 10, 12:42 PM UTC: Merged by the Graphite merge queue.

@graphite-app graphite-app bot force-pushed the om/03-09-perf_linter_plugins_pre-populate_cache_of_visitprop_objects branch from b2e9703 to 8742f8b Compare March 10, 2026 11:50
graphite-app bot pushed a commit that referenced this pull request Mar 10, 2026
Perf optimization to visitor compilation.

Replace 3 x `Arrays` with `Uint8Array`s. These arrays only contain positive integers between 0 and 171, so `Uint8Array`s are more suitable. Each entry takes 1 byte instead of 8 bytes, and the entries are strictly typed so should help V8 to optimize.

Resetting these arrays is also cheaper, and will never result in allocations, which the original `Array`s likely did.
@graphite-app graphite-app bot force-pushed the om/03-09-perf_linter_plugins_replace_arrays_with_uint8array_s branch from 576c42b to d2173b8 Compare March 10, 2026 11:50
@graphite-app graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Mar 10, 2026
Base automatically changed from om/03-09-perf_linter_plugins_pre-populate_cache_of_visitprop_objects to main March 10, 2026 12:02
@overlookmotel overlookmotel added the 0-merge Merge with Graphite Merge Queue label Mar 10, 2026
Perf optimization to visitor compilation.

Replace 3 x `Arrays` with `Uint8Array`s. These arrays only contain positive integers between 0 and 171, so `Uint8Array`s are more suitable. Each entry takes 1 byte instead of 8 bytes, and the entries are strictly typed so should help V8 to optimize.

Resetting these arrays is also cheaper, and will never result in allocations, which the original `Array`s likely did.
@graphite-app graphite-app bot force-pushed the om/03-09-perf_linter_plugins_replace_arrays_with_uint8array_s branch from d2173b8 to d243391 Compare March 10, 2026 12:32
@graphite-app graphite-app bot merged commit d243391 into main Mar 10, 2026
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@graphite-app graphite-app bot deleted the om/03-09-perf_linter_plugins_replace_arrays_with_uint8array_s branch March 10, 2026 12:42
@graphite-app graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Mar 10, 2026
leaysgur added a commit that referenced this pull request Mar 11, 2026
# Oxlint
### 🚀 Features

- 04a5ce0 oxlint: Support `vite.config.ts` `.lint` field (#20214)
(leaysgur)
- 1735215 linter: Implement `react/no-clone-element` rule. (#20129)
(connorshea)
- 68e6f6f linter: Implement `react/no-react-children` rule. (#20104)
(connorshea)
- fe3b32e linter/plugins: Add `oxlint-plugin-eslint` package (#20009)
(overlookmotel)

### 🐛 Bug Fixes

- 05f6a09 linter/no-inline-comments: Deserialize rule options with serde
(#20207) (camc314)
- c7eb09d linter/default-case: Deserialize rule options with serde
(#20206) (camc314)
- f85e16c linter/plugins: Fix types for visitor compilation (#20203)
(overlookmotel)
- 44e24e0 linter/exhaustive-deps: Ignore type-only typeof deps (#20201)
(camc314)
- 0b04998 linter/no-fallthrough: Deserialize rule options with serde
(#20192) (camc314)
- a1031cb linter/new-cap: Deserialize rule options with serde (#20161)
(camc314)
- ad27fd6 linter: Add help messages to import plugin diagnostics
(#20158) (John Costa)
- 1340307 linter/plugins: Ensure `after` hooks always run (#20167)
(overlookmotel)
- c4812ec linter/plugins: Reset visitor compilation state if error
during compilation (#20166) (overlookmotel)
- 887eecc linter/plugins: Add license notice to `oxlint-plugin-eslint`
package (#20164) (overlookmotel)
- e1713a4 linter/plugins: Include common chunks in
`oxlint-plugin-eslint` package (#20163) (overlookmotel)
- a9acb2b linter: Check `globals` entry for `no-undef`, only check
es2026 globals for `no-extend-native` and
`no-constant-binary-expression` (#20089) (Sysix)
- 5559f0d linter/no-unused-vars: `reportUsedIgnorePattern` should not
report used rest siblings (#20108) (Don Isaac)
- de7c0e2 linter/plugins: Correct error message for `markVariableAsUsed`
(#20152) (overlookmotel)

### ⚡ Performance

- 3a86427 linter/plugins: Pre-populate cache of `EnterExit` objects at
startup (#20194) (overlookmotel)
- d243391 linter/plugins: Replace arrays with `Uint8Array`s (#20190)
(overlookmotel)
- 8742f8b linter/plugins: Pre-populate cache of `VisitProp` objects
(#20189) (overlookmotel)
- 3061acb linter/plugins: Pre-populate cache of `EnterExit` objects
(#20187) (overlookmotel)
- c73912b linter/plugins: Free visit functions earlier (#20186)
(overlookmotel)
- d9f8ff4 linter/plugins: Faster reset of visitor state (#20185)
(overlookmotel)
- 42aff15 oxlint/lsp: Avoid computing diagnostics for non invoked code
actions requests (#20080) (Sysix)

### 📚 Documentation

- a080650 linter/plugins: Fix documentation of visitor compilation
(#20202) (overlookmotel)
- 542a04a linter: Add a link to the cyclomatic complexity Wikipedia
article in `eslint/complexity` (#20174) (connorshea)
# Oxfmt
### 🚀 Features

- 95943aa oxfmt: Support `vite.config.*` `.fmt` field (#20197)
(leaysgur)
- 172fc07 oxfmt: .js/.ts config file support (#20135) (leaysgur)

### 🐛 Bug Fixes

- e483569 oxfmt: Avoid double-escaping in css-in-js (#20211) (leaysgur)

Co-authored-by: leaysgur <6259812+leaysgur@users.noreply.github.com>
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