perf(linter/plugins): lazy-load tokens parsing code #16011

overlookmotel · 2025-11-23T22:14:37Z

Tokens APIs (#15861 and further PRs) utilize TS-ESLint for parsing. TS-ESLint uses TypeScript internally. So this pulls in a ton of code (8 MB unminified).

Lazy-load this code only when tokens APIs are used for the first time, so that users don't pay for it if their plugins don't use these APIs (or plugins only use tokens APIs for fixes, and the code being linted has no errors that require fixing).

Do this by compiling @typescript-eslint/typescript-estree into a separate bundle. It's bundled as CommonJS, so it can be synchonously require-ed without needing require(esm) support.

Additionally, minify this bundle, which cuts the increase in package size due to TS-ESLint from 8 MB to 3.7 MB. That's still a lot, but not completely unacceptable, given that the oxlint binary is around 9.3 MB. As soon as we can, we'll re-implement token-generation in Oxc parser, and then we'll be able to remove TS-ESLint again.

overlookmotel · 2025-11-23T22:14:51Z

perf(linter/plugins): lazy-load tokens parsing code #16011 👈 (View in Graphite)
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overlookmotel · 2025-11-23T22:29:47Z

@camc314 I'd appreciate your review on this, but I want to make sure it gets in to tomorrow's release, so I'm going to merge it now, and we can make any changes tomorrow morning before cutting release if required.

cc @lilnasy FYI.

overlookmotel · 2025-11-23T22:29:59Z

Merge activity

Nov 23, 10:29 PM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Nov 23, 10:30 PM UTC: overlookmotel added this pull request to the Graphite merge queue.
Nov 23, 10:36 PM UTC: Merged by the Graphite merge queue.

Tokens APIs (#15861 and further PRs) utilize TS-ESLint for parsing. TS-ESLint uses TypeScript internally. So this pulls in a ton of code (8 MB unminified). Lazy-load this code only when tokens APIs are used for the first time, so that users don't pay for it if their plugins don't use these APIs (or plugins only use tokens APIs for fixes, and their code has no errors that require fixes). Do this by compiling `@typescript-eslint/typescript-estree` into a separate bundle. It's bundled as CommonJS, so it can be synchonously `require`-ed without needing `require(esm)` support. Additionally, minify this bundle, which cuts the increase in package size due to TS-ESLint from 8 MB to 3.7 MB. That's still a lot, but not *completely* unacceptable, given that the `oxlint` binary is around 9.3 MB. As soon as we can, we'll re-implement token-generation in Oxc parser, and then we'll be able to remove TS-ESLint again.

Copilot

Pull request overview

This PR implements lazy-loading of the TypeScript ESLint parser to improve oxlint's performance by deferring the loading of ~8MB of parsing code until token APIs are first used. The implementation creates a separate bundled artifact for @typescript-eslint/typescript-estree and loads it on-demand using Node.js's createRequire.

Key changes:

Separated TypeScript ESLint parser into its own minified CommonJS bundle
Implemented lazy-loading in tokens.ts using createRequire
Refactored tsdown.config.ts to support multiple build configurations

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
apps/oxlint/tsdown.config.ts	Restructured build config to output two separate bundles: main ESM bundle and minified CommonJS bundle for TS-ESLint
apps/oxlint/src-js/plugins/ts_eslint.cjs	New entry point that re-exports @typescript-eslint/typescript-estree for bundling
apps/oxlint/src-js/plugins/tokens.ts	Replaced static import with lazy-loading via createRequire to defer TS-ESLint loading until first token API use

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apps/oxlint/tsdown.config.ts

apps/oxlint/src-js/plugins/tokens.ts

camc314

We need import defer 😉

lgtm

overlookmotel · 2025-11-23T23:18:21Z

Even import defer eagerly parses the code, it only defers evaluation (or so one of the Bloombergers at ViteConf was telling me). So dynamic require / import is here to stay, it seems...

# Oxlint ### 💥 BREAKING CHANGES - cbb27fd ast: [**BREAKING**] Add `TSGlobalDeclaration` type (#15712) (overlookmotel) ### 🚀 Features - 72660f7 linter: Support auto generate config document for tuple lint option (#15904) (Duc Nghiem Xuan) - 0c1f82b linter/plugins: Add `tokens` property to `Program` (#16020) (overlookmotel) - 9e61beb linter/plugins: Implement `SourceCode#getFirstToken()` (#16002) (Arsh) - 9a548dd linter/plugins: Implement `SourceCode#getLastTokens()` (#16000) (Arsh) - 0b6cb11 linter/plugins: Implement `SourceCode#getFirstTokens()` (#15976) (Arsh) - 166781e linter/plugins: Implement `SourceCode#getTokenAfter()` (#15973) (Arsh) - 6ae232b linter: Expose type errors via tsgolint (#15917) (camc314) - 2bfdd26 linter/plugins: Implement `SourceCode#getTokensAfter()` (#15971) (Arsh) - 45fffc1 linter/plugins: Implement `SourceCode#getTokenBefore()` (#15956) (Arsh) - 776e473 linter/plugins: Implement `SourceCode#getTokensBefore()` (#15955) (Arsh) - 595867a oxlint: Generate markdownDescription fields for oxlint JSON schema. (#15959) (connorshea) - 5569317 vscode: Add quick actions to status bar tooltip (#15962) (Sysix) - 986cac1 linter/plugins: Token-related `SourceCode` APIs (TS ESLint implementation) (#15861) (Arsh) - a21f9e4 linter: Implement unicorn/prefer-bigint-literals rule (#15923) (Michiel Vrins) - 4b9d8d2 linter/type-aware: Include range with tsconfig diagnostics (#15916) (camc314) - 220d01e editor: Improve the status bar item for the VS Code extension by adding a tooltip. (#15819) (connorshea) ### 🐛 Bug Fixes - 2bd3cb6 apps, editors, napi: Fix `oxlint-disable` comments (#16014) (overlookmotel) - 81f5360 linter/prefer-number-properties: Get fixer to replace entire call expr (#15979) (camc314) - e4ba07f language_server: Always write to memory file system (#15975) (Sysix) - a8a2032 linter: Support missing `range` for internal diagnostics (#15964) (camc314) - 619a226 oxlint/lsp: Don't register `textDocument/formatting` capability (#15882) (Sysix) - 6ab1a20 linter: Fix no_useless_spread producing invalid syntax when removing empty object spreads (#15905) (camc314) - be4b6df linter: Unicorn/prefer-string-replace-all incorrectly escapes backslashes (#15901) (camc314) - 9fa9ef2 linter: Gracefully fail when using import plugin, large file counf and JS plugins (#15864) (camc314) - c027398 linter/plugins: Correct bindings package names glob in TSDown config (#15871) (overlookmotel) - b622ef8 linter: Fix `oxc/bad_array_method_on_arguments` rule behavior. (#15854) (connorshea) - aa06c3f linter: Recognize NewExpression as value context in no-unused-private-class-members (#15843) (camc314) - e89c5ba typescript/prefer-namespace-keyword: Skip nested `TSModuleDeclaration`s (#15806) (overlookmotel) - 646d020 linter/exhaustive-dependencies: Prevent is_callee_of_call_expr flag from leaking into nested expressions (#15832) (camc314) - 46bd6bd linter/plugins: Pin `@typescript-eslint/scope-manager` dependency (#15807) (overlookmotel) - fba31fa linter: Patch `@typescript-eslint/scope manager` (#15214) (Arsh) - 50307c1 linter/jest: Ignore `expect` identifier in argument position (#15785) (camc314) ### ⚡ Performance - 024b48a linter/plugins: Lazy-load tokens parsing code (#16011) (overlookmotel) - 15365c9 linter/plugins: Reduce var assignments (#15953) (overlookmotel) - 84d1f4f linter/plugins: Downgrade some checks to debug-only (#15922) (overlookmotel) - a49f704 linter/typescript: Avoid searching source text unless required (#15805) (overlookmotel) ### 📚 Documentation - ceffa5a linter: Add config option docs for various rules. (#16024) (connorshea) - 9a0ed13 linter: Fix config option docs for eslint/operator-assignment rule. (#16030) (connorshea) - 0b18005 linter: Add config docs generation for rules with Regex arguments (#15978) (connorshea) - 48d18e0 linter: Improve diagnostic message for promise/catch-or-return rule (#15980) (connorshea) - 6c72e84 linter: Use backticks for code elements across more rule diagnostics (#15958) (connorshea) - a63dad7 linter/plugins: Add comment (#15952) (overlookmotel) - 81ea642 vscode: Use markdownDescription for better formatting in VSCode Settings (#15889) (connorshea) - db6a110 linter/plugins: Fix JSDoc comment (#15884) (overlookmotel) - 1487271 linter: Add config option docs for `jsdoc/require-param` and `jsdoc/require-returns` rules (#15857) (connorshea) - fbf0fd4 linter/plugins: Add JSDoc comments to `Plugin` and `Rule` types (#15815) (overlookmotel) - ac5e4b5 linter/plugins: Add JSDoc comments and improve comments (#15814) (overlookmotel) - 9b7b083 linter: Fix error in `curly` `"all"` example (#15801) (camc314) - 65a3520 linter: Improve diagnostic for consistent-type-definitions rule. (#15752) (connorshea) ### 🛡️ Security - f9b9276 deps: Update dependency rolldown to v1.0.0-beta.51 (#15856) (renovate[bot]) # Oxfmt ### 💥 BREAKING CHANGES - a937890 formatter: [**BREAKING**] Default to `lineWidth: 100` (#15933) (leaysgur) - 03d5f5a formatter/sort-imports: [**BREAKING**] Change default order to `natural` with `natord` crate (#15828) (leaysgur) - cbb27fd ast: [**BREAKING**] Add `TSGlobalDeclaration` type (#15712) (overlookmotel) ### 🚀 Features - 7818e22 formatter/sort-imports: Support `options.groups` (#15831) (leaysgur) - f9a502c oxfmt: `oxfmt --lsp` support (#15765) (leaysgur) ### 🐛 Bug Fixes - 4817486 formatter: Revert `FormatElement::BestFitting` printing logic (#16028) (Dunqing) - 5562dd6 formatter: Incorrect formatting method chain with trailing comments (#16027) (Dunqing) - 6d14c8b formatter: Comments in export class decorators are printing incorrectly (#15897) (Dunqing) - 683c764 formatter: Correct a few minor mismatched typescript tests (#15894) (Dunqing) - c11cc07 formatter: Improve formatting for default type on type parameters (#15893) (Dunqing) - 0bff596 formatter: Handle JSX expresssion dangling comment (#15890) (leaysgur) - 16a9dc8 formatter: Inconsistent printing of class extends and interface extends (#15892) (Dunqing) - 300b496 formatter: Inconsistent CallExpression and NewExpression around member chain and logical expression (#15858) (Dunqing) ### ⚡ Performance - 65174cc formatter: Reduce the size of `TextWidth` to 4 byte (#15827) (Dunqing) - 4fe3aac formatter: Use `ArenaVec` and `ArenaBox` (#15420) (Dunqing) Co-authored-by: overlookmotel <557937+overlookmotel@users.noreply.github.com>

github-actions bot added A-linter Area - Linter A-cli Area - CLI A-linter-plugins Area - Linter JS plugins labels Nov 23, 2025

github-actions bot added the C-performance Category - Solution not expected to change functional behavior, only performance label Nov 23, 2025

overlookmotel marked this pull request as ready for review November 23, 2025 22:27

overlookmotel requested a review from camc314 as a code owner November 23, 2025 22:27

Copilot AI review requested due to automatic review settings November 23, 2025 22:27

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graphite-app bot force-pushed the 11-23-perf_linter_plugins_lazy-load_tokens_parsing_code branch from 4b61b41 to 024b48a Compare November 23, 2025 22:30

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graphite-app bot merged commit 024b48a into main Nov 23, 2025
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graphite-app bot deleted the 11-23-perf_linter_plugins_lazy-load_tokens_parsing_code branch November 23, 2025 22:36

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This was referenced Nov 24, 2025

release(apps): oxlint v1.30.0 && oxfmt v0.15.0 #16039

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release(apps): oxlint v1.30.0 && oxfmt v0.15.0 #16047

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lilnasy mentioned this pull request Nov 24, 2025

feat(linter/plugins): Token-related SourceCode APIs (TS ESLint implementation) #15861

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perf(linter/plugins): lazy-load tokens parsing code #16011

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