type aware linting blog post

Author: Boshen

.vitepress/config/en.ts

@@ -23,7 +23,7 @@ export const enConfig = defineLocaleConfig("root", {
       {
         text: "Resources",
         items: [
-          { text: "Blog", link: "/blog/2025-06-10-oxlint-stable" },
+          { text: "Blog", link: "/blog/2025-08-17-oxlint-type-aware" },
           { text: "Team", link: "/team" },
           { text: "Branding", link: "/branding" },
           { text: "Website GitHub", link: "https://github.com/oxc-project/oxc-project.github.io" },

.vitepress/config/inlined-scripts/banner.js

@@ -6,6 +6,6 @@
     }
   };
 
-  window.__OXC_BANNER_ID__ = "/blog/2025-06-10-oxlint-stable";
+  window.__OXC_BANNER_ID__ = "/blog/2025-08-17-oxlint-type-aware";
   restore(`oxc-banner-dismissed-${__OXC_BANNER_ID__}`, "banner-dismissed");
 })();

.vitepress/sidebar.blog.json

@@ -1,4 +1,8 @@
 [
+  {
+    "text": "Oxlint Type-Aware Preview",
+    "link": "/blog/2025-08-17-oxlint-type-aware"
+  },
   {
     "text": "Oxlint v1.0 Stable",
     "link": "/blog/2025-06-10-oxlint-stable"

.vitepress/theme/components/Banner.vue

@@ -17,7 +17,7 @@ const hide = () => {
 };
 
 // Sync with inlined-scripts/banner.js
-const slug = "/blog/2025-06-10-oxlint-stable";
+const slug = "/blog/2025-08-17-oxlint-type-aware";
 
 const bannerDismissed = useLocalStorage<boolean>(`oxc-banner-dismissed-${slug}`, false);
 
@@ -46,7 +46,7 @@ const dismiss = () => {
 
 <template>
   <div ref="el" class="banner banner-dismissed">
-    <div class="text"><a :href="slug">Announcing Oxlint v1.0 Stable</a> 🎉</div>
+    <div class="text"><a :href="slug">Announcing Oxlint Type-Aware Preview</a> 🎉</div>
 
     <button type="button" @click="dismiss">
       <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20" fill="currentColor">

.vitepress/theme/constants/team.ts

@@ -152,6 +152,18 @@ export const CORE_MEMBERS: TeamMember[] = [
       { icon: "x", link: "https://x.com/yagiznizipli" },
     ],
   },
+  {
+    id: "auvred",
+    type: "consultant",
+    name: "auvred",
+    title: "tsgolint",
+    avatar: "https://www.github.com/auvred.png",
+    org: "typescript-eslint",
+    orgLink: "https://github.com/typescript-eslint",
+    links: [
+      { icon: "github", link: "https://github.com/auvred" },
+    ],
+  },
 ];
 
 export const CORE_TEAM_MEMBERS = CORE_MEMBERS.filter(({ type }) => type === "core") as CoreTeamMember[];

src/blog/2025-08-17-oxlint-type-aware.md

@@ -0,0 +1,269 @@
+---
+title: Oxlint Type-Aware Preview
+outline: deep
+authors:
+  - boshen
+  - auvred
+  - camchenry
+  - cameron
+---
+
+<AppBlogPostHeader />
+
+<br>
+
+We're thrilled to announce type-aware linting in `oxlint`!
+
+The long-awaited `no-floating-promises` and related rules are here.
+
+This preview release aims to engage with the community for collaboration and
+discussion by documenting our decision process and technical details.
+
+## Quick Start
+
+If `oxlint` is already configured, install `oxlint-tsgolint` and run `oxlint` with the `--type-aware` flag:
+
+```bash
+pnpm add -D oxlint-tsgolint@latest
+pnpm dlx oxlint --type-aware
+```
+
+If `oxlint` is not configured but you want to see `no-floating-promises` in action:
+
+```bash
+pnpm add -D oxlint-tsgolint@latest
+pnpm dlx oxlint@latest --type-aware -A all -D typescript/no-floating-promises
+```
+
+We expect to see, for example:
+
+```js
+ × typescript-eslint(no-floating-promises): Promises must be awaited, end with a call to .catch, end with a call to .then with a rejection handler or be explicitly marked as ignored with the `void` operator.
+   ╭─[packages/rolldown/src/api/watch/watcher.ts:30:7]
+29 │       await this.close();
+30 │       originClose();
+   ·       ──────────────
+31 │     };
+   ╰────
+```
+
+Please visit our [usage guide](https://oxc.rs/docs/guide/usage/linter.html) for more configuration options.
+
+## Performance
+
+Our testing shows that repositories which previously took a minute to run with `typescript-eslint` now complete in less than 10 seconds.
+
+This is achieved by leveraging [`typescript-go`](https://github.com/microsoft/typescript-go),
+the [10x faster TypeScript](https://devblogs.microsoft.com/typescript/typescript-native-port) written in Go.
+
+Using projects from [oxlint-ecosystem-ci](https://github.com/oxc-project/oxlint-ecosystem-ci):
+
+| Project  | Files | Time |
+| -------- | ----- | ---- |
+| napi-rs  | 144   | 1.0s |
+| preact   | 245   | 2.7s |
+| rolldown | 314   | 1.5s |
+| bluesky  | 1152  | 7.0s |
+
+## Type-Aware Linting
+
+Please refer to
+[Rust-Based JavaScript Linters: Fast, But No Typed Linting Right Now](https://www.joshuakgoldberg.com/blog/rust-based-javascript-linters-fast-but-no-typed-linting-right-now)
+to understand the current status of type-aware linting in the ecosystem.
+
+## Technical Details
+
+The core of this new functionality is [oxc-project/tsgolint](https://github.com/oxc-project/tsgolint).
+
+The `tsgolint` project was initially prototyped as [typescript-eslint/tsgolint](https://github.com/typescript-eslint/tsgolint).
+However, the `typescript-eslint` team decided not to allocate development resources to this prototype, as they plan to continue their work on `typescript-eslint` for typed linting with ESLint.
+
+[@boshen](https://github.com/Boshen) reached out to [@auvred](https://github.com/auvred) for a forked, scoped-down version adapted for oxlint.
+This version would only contain type-aware rules without the sophisticated configuration resolution a full linter would require.
+
+[@auvred](https://github.com/auvred) generously offered to continue its development under the Oxc organization.
+
+### Architecture
+
+`oxlint` (written in Rust) and `tsgolint` (written in Go) are compiled into their own binaries.
+
+`oxlint` serves as the "frontend" for `tsgolint`, handling the CLI, path traversal, ignore logic, and diagnostic printing.
+
+`tsgolint` acts as the backend for `oxlint`, accepting paths and configuration as input and outputting structured diagnostics.
+
+This creates a simple pipeline:
+
+```
+oxlint CLI (returns paths + rules + configuration)
+  -> tsgolint (returns diagnostics)
+  -> oxlint CLI (prints diagnostics)
+```
+
+### `tsgolint`
+
+`tsgolint` does not communicate with typescript-go via public APIs.
+
+Instead, it compiles `typescript-go` by [shimming](https://github.com/oxc-project/tsgolint/tree/main/shim) its internal APIs to make them public.
+
+All type-aware rules are written directly against these shimmed APIs.
+
+While this isn't the recommended approach for accessing internals, it works!
+
+## Decision Process
+
+### Write our own type checker
+
+Previous abandoned attempts to implement a type-checker included:
+
+- My own attempt at [writing type inference](https://gist.github.com/Boshen/d189de0fe0720a30c5182cb666e3e9a5)
+- [Integrate](https://github.com/oxc-project/oxc/pull/413) [ezno type checker](https://github.com/kaleidawave/ezno) by [@kaleidawave](https://github.com/kaleidawave)
+- [stc](https://github.com/dudykr/stc) by [@kdy1](https://github.com/kdy1)
+- There are also many attempts in the community that did not go far.
+
+Additionally, there's the work-in-progress [Biome 2.0](https://biomejs.dev/blog/biome-v2/) with its own type-inference implementation.
+
+We determined that writing our own type-inferencer or type-checker was not feasible due to
+the challenge of keeping up with a fast-moving target like TypeScript.
+
+### Communication with TypeScript Compiler
+
+Prior to `typescript-go`, projects added plugin interfaces to TypeScript's public API by either mapping its AST to `estree` or directly traversing the TypeScript AST. Examples include:
+
+- [typescript-eslint](https://typescript-eslint.io/getting-started/typed-linting)
+- [tsslint](https://github.com/johnsoncodehk/tsslint)
+- [tsl](https://github.com/ArnaudBarre/tsl)
+
+We also explored [inter-process communication with oxlint](https://github.com/oxc-project/oxc/discussions/2855) but abandoned the idea.
+
+With `typescript-go`, the TypeScript team is [leaning towards](https://github.com/microsoft/typescript-go/discussions/455)
+encoding the TypeScript AST and decoding it on the JavaScript side through inter-process communication.
+
+While these approaches work, they still incur:
+
+- Performance issues of varying degrees that don't suit oxlint's performance characteristics.
+- The cost of maintaining an AST mapping from TypeScript's AST.
+
+## Considerations
+
+While `tsgolint` solves the performance issue, there are other technical challenges that need to be addressed.
+
+### Requirement for a Different TypeScript Version
+
+We plan to release snapshots of `typescript-go` versions and align their version numbers with TypeScript.
+You will then be able to install `oxlint-typescript` with the correct TypeScript version.
+
+The downside of this approach is that you may need to upgrade TypeScript if `oxlint-tsgolint` requires changes.
+
+### Maintenance cost of `tsgolint`
+
+Shimming TypeScript's internal APIs carries some risk. However, the TypeScript AST and its visitor are actually quite stable.
+We accept this risk and will fix breaking changes when upgrading `typescript-go`.
+
+Our `typescript-go` version is synced every day.
+
+## Performance Issues
+
+`tsgolint` currently does not perform well on large monorepos with hundreds of projects or lots of project references.
+
+It may hang with a deadlock or cause OOM (out-of-memory) if a bug is encountered.
+
+We are actively addressing these issues, profiling and submitting improves to `typescript-go`, benefiting all `typescript-go` users.
+
+Our core team member [@camc314](https://github.com/camc314) has already submitted [many PRs](https://github.com/microsoft/typescript-go/pulls?q=is%3Apr+author%3Acamc314+) that made several code paths significantly faster.
+
+## v1.0 Release
+
+For `tsgolint` v1.0, we will address:
+
+- performance issue for large monorepos
+- be able to configure individual rules
+- correctness of each individual rules
+- IDE support
+- overall stability
+
+## Acknowledgements
+
+We'd like to extend our gratitude to:
+
+- The TypeScript team for creating `typescript-go`.
+- The `typescript-eslint` team for their heartwarming support.
+- [@auvred](https://github.com/auvred) for creating `tsgolint`.
+- [@camchenry](https://github.com/camchenry) for the `oxlint` + `tsgolint` integration.
+- [@camc314](https://github.com/camc314) for work on performance issues.
+
+## Join the Community
+
+We'd love to hear your feedback on `oxlint` and type-aware linting and are excited to see how it helps improve your development workflow.
+
+Connect with us:
+
+- **Discord**: Join our [community server](https://discord.gg/9uXCAwqQZW) for real-time discussions
+- **GitHub**: Share feedback on [GitHub Discussions](https://github.com/oxc-project/oxc/discussions)
+- **Issues**: Report `oxlint` bugs to [oxc](https://github.com/oxc-project/oxc/issues) and type-aware linting bugs to [tsgolint](https://github.com/oxc-project/tsgolint/issues).
+
+## Next steps
+
+Install `oxlint`:
+
+```bash
+pnpm add -D oxlint@latest oxlint-tsgolint@latest
+pnpm dlx oxlint --init # generate .oxlintrc.json
+```
+
+or follow the [installation guide](https://oxc.rs/docs/guide/usage/linter).
+
+Use the `--type-aware` CLI flag.
+
+```bash
+pnpm dlx oxlint --type-aware
+```
+
+And play around with any of the type-aware rules in `.oxlintrc.json`:
+
+```json
+{
+  "$schema": "./node_modules/oxlint/configuration_schema.json",
+  "rules": {
+    "typescript/await-thenable": "error",
+    "typescript/no-array-delete": "error",
+    "typescript/no-base-to-string": "error",
+    "typescript/no-confusing-void-expression": "error",
+    "typescript/no-duplicate-type-constituents": "error",
+    "typescript/no-floating-promises": "error",
+    "typescript/no-for-in-array": "error",
+    "typescript/no-implied-eval": "error",
+    "typescript/no-meaningless-void-operator": "error",
+    "typescript/no-misused-promises": "error",
+    "typescript/no-misused-spread": "error",
+    "typescript/no-mixed-enums": "error",
+    "typescript/no-redundant-type-constituents": "error",
+    "typescript/no-unnecessary-boolean-literal-compare": "error",
+    "typescript/no-unnecessary-template-expression": "error",
+    "typescript/no-unnecessary-type-arguments": "error",
+    "typescript/no-unnecessary-type-assertion": "error",
+    "typescript/no-unsafe-argument": "error",
+    "typescript/no-unsafe-assignment": "error",
+    "typescript/no-unsafe-call": "error",
+    "typescript/no-unsafe-enum-comparison": "error",
+    "typescript/no-unsafe-member-access": "error",
+    "typescript/no-unsafe-return": "error",
+    "typescript/no-unsafe-type-assertion": "error",
+    "typescript/no-unsafe-unary-minus": "error",
+    "typescript/non-nullable-type-assertion-style": "error",
+    "typescript/only-throw-error": "error",
+    "typescript/prefer-promise-reject-errors": "error",
+    "typescript/prefer-reduce-type-parameter": "error",
+    "typescript/prefer-return-this-type": "error",
+    "typescript/promise-function-async": "error",
+    "typescript/related-getter-setter-pairs": "error",
+    "typescript/require-array-sort-compare": "error",
+    "typescript/require-await": "error",
+    "typescript/restrict-plus-operands": "error",
+    "typescript/restrict-template-expressions": "error",
+    "typescript/return-await": "error",
+    "typescript/switch-exhaustiveness-check": "error",
+    "typescript/unbound-method": "error",
+    "typescript/use-unknown-in-catch-callback-variable": "error"
+  }
+}
+```