refactor(linter): extract vite lint config in JS loader

apps/oxlint/src-js/js_config.ts

@@ -1,3 +1,5 @@
+import { basename as pathBasename } from "node:path";
+
 import { getErrorMessage } from "./utils/utils.ts";
 import { isDefineConfig } from "./package/config.ts";
 import { DateNow, JSONStringify } from "./utils/globals.ts";
@@ -12,6 +14,9 @@ type LoadJsConfigsResult =
   | { Failures: { path: string; error: string }[] }
   | { Error: string };
 
+const VITE_CONFIG_NAME = "vite.config.ts";
+const VITE_OXLINT_CONFIG_FIELD = "lint";
+
 function validateConfigExtends(root: object): void {
   const visited = new WeakSet<object>();
   const inStack = new WeakSet<object>();
@@ -95,7 +100,7 @@ export async function loadJsConfigs(paths: string[]): Promise<string> {
         // Bypass Node.js module cache to allow reloading changed config files (used for LSP, where we reload configs after important changes)
         const fileUrl = new URL(`file://${path}?cache=${cacheKey}`);
         const module = await import(fileUrl.href);
-        const config = module.default;
+        let config = module.default;
 
         if (config === undefined) {
           throw new Error(`Configuration file has no default export.`);
@@ -105,19 +110,23 @@ export async function loadJsConfigs(paths: string[]): Promise<string> {
           throw new Error(`Configuration file must have a default export that is an object.`);
         }
 
-        // Vite config files (e.g. `vite.config.ts`) are not Oxlint configs,
-        // so skip `defineConfig()` and `extends` validation.
-        // The `.lint` field extraction is handled on the Rust side.
-        if (!path.endsWith("/vite.config.ts")) {
+        if (pathBasename(path) === VITE_CONFIG_NAME) {
+          config = (config as Record<string, unknown>)[VITE_OXLINT_CONFIG_FIELD] ?? {};
+          if (typeof config !== "object" || config === null || Array.isArray(config)) {
+            throw new Error(
+              `The \`${VITE_OXLINT_CONFIG_FIELD}\` field in the default export must be an object.`,
+            );
+          }
+        } else {
           if (!isDefineConfig(config)) {
             throw new Error(
               `Configuration file must wrap its default export with defineConfig() from "oxlint".`,
             );
           }
-
-          validateConfigExtends(config as object);
         }
 
+        validateConfigExtends(config as object);
+
         return { path, config };
       }),
     );

apps/oxlint/src/js_config.rs

@@ -5,7 +5,6 @@ use oxc_diagnostics::OxcDiagnostic;
 use oxc_linter::Oxlintrc;
 
 use crate::run::JsLoadJsConfigsCb;
-use crate::{VITE_CONFIG_NAME, VITE_OXLINT_CONFIG_FIELD};
 
 /// Callback type for loading JavaScript/TypeScript config files.
 pub type JsConfigLoaderCb =
@@ -119,27 +118,7 @@ fn parse_js_config_response(json: &str) -> Result<Vec<JsConfigResult>, Vec<OxcDi
                 (Vec::with_capacity(count), Vec::new()),
                 |(mut configs, mut errors), entry| {
                     let path = PathBuf::from(&entry.path);
-
-                    // Vite config files: extract the `.lint` field
-                    let is_vite_config = path
-                        .file_name()
-                        .and_then(|f| f.to_str())
-                        .is_some_and(|name| name == VITE_CONFIG_NAME);
-                    let config_value = if is_vite_config {
-                        if let Some(v) = entry.config.get(VITE_OXLINT_CONFIG_FIELD).cloned() {
-                            v
-                        } else {
-                            errors.push(OxcDiagnostic::error(format!(
-                                "Expected a `{VITE_OXLINT_CONFIG_FIELD}` field in the default export of {}",
-                                entry.path
-                            )));
-                            return (configs, errors);
-                        }
-                    } else {
-                        entry.config
-                    };
-
-                    let mut oxlintrc = match parse_js_oxlintrc(config_value) {
+                    let mut oxlintrc = match parse_js_oxlintrc(entry.config) {
                         Ok(config) => config,
                         Err(err) => {
                             errors.push(
@@ -185,3 +164,36 @@ fn parse_js_config_response(json: &str) -> Result<Vec<JsConfigResult>, Vec<OxcDi
         }
     }
 }
+
+#[cfg(test)]
+mod test {
+    use serde_json::json;
+
+    use super::parse_js_config_response;
+
+    #[test]
+    fn test_parse_js_config_response_accepts_vite_lint_payloads() {
+        let path = std::env::temp_dir().join("vite.config.ts");
+        let json = serde_json::to_string(&json!({
+            "Success": [{
+                "path": path,
+                "config": {
+                    "options": { "typeAware": true },
+                    "extends": [{
+                        "options": { "typeCheck": true }
+                    }]
+                }
+            }]
+        }))
+        .unwrap();
+
+        let configs = parse_js_config_response(&json).unwrap();
+        assert_eq!(configs.len(), 1);
+
+        let config = &configs[0].config;
+        assert_eq!(config.path, path);
+        assert_eq!(config.options.type_aware, Some(true));
+        assert_eq!(config.extends_configs.len(), 1);
+        assert_eq!(config.extends_configs[0].options.type_check, Some(true));
+    }
+}

apps/oxlint/src/lib.rs

@@ -61,7 +61,6 @@ const DEFAULT_JSONC_OXLINTRC_NAME: &str = ".oxlintrc.jsonc";
 const DEFAULT_TS_OXLINTRC_NAME: &str = "oxlint.config.ts";
 /// Vite config file that may contain oxlint config under a `.lint` field.
 const VITE_CONFIG_NAME: &str = "vite.config.ts";
-const VITE_OXLINT_CONFIG_FIELD: &str = "lint";
 
 /// Return a JSON blob containing metadata for all available oxlint rules.
 ///

apps/oxlint/test/fixtures/vite_config_no_lint_field/output.snap.md

@@ -1,11 +1,17 @@
 # Exit code
-1
+0
 
 # stdout
 ```
-Failed to parse oxlint configuration file.
+  ! eslint(no-debugger): `debugger` statement is not allowed
+   ,-[files/test.js:1:1]
+ 1 | debugger;
+   : ^^^^^^^^^
+   `----
+  help: Remove the debugger statement
 
-  x Expected a `lint` field in the default export of <fixture>/vite.config.ts
+Found 1 warning and 0 errors.
+Finished in Xms on 1 file with 93 rules using X threads.
 ```
 
 # stderr