feat(oxfmt): Support vite.config.* .fmt field

apps/oxfmt/src/cli/format.rs

@@ -217,6 +217,7 @@ impl FormatRunner {
             );
             // Config stats: only show when no config is found
             if oxfmtrc_path.is_none() && editorconfig_path.is_none() {
+                #[cfg(feature = "napi")]
                 let hint = "No config found, using defaults. Please add a config file or try `oxfmt --init` if needed.\n";
                 #[cfg(not(feature = "napi"))]
                 let hint =

apps/oxfmt/src/core/config.rs

@@ -23,16 +23,24 @@ use super::{
 };
 
 /// JSON/JSONC config file names, in order of preference.
-pub const JSON_CONFIG_FILES: &[&str] = &[".oxfmtrc.json", ".oxfmtrc.jsonc"];
-/// JS/TS config file names, in order of preference.
-pub const JS_CONFIG_FILES: &[&str] = &[
-    "oxfmt.config.ts",
-    "oxfmt.config.mts",
-    "oxfmt.config.cts",
-    "oxfmt.config.js",
-    "oxfmt.config.mjs",
-    "oxfmt.config.cjs",
-];
+const JSON_CONFIG_FILES: &[&str] = &[".oxfmtrc.json", ".oxfmtrc.jsonc"];
+/// JS/TS config file extensions.
+const JS_CONFIG_EXTENSIONS: &[&str] = &["ts", "mts", "cts", "js", "mjs", "cjs"];
+/// Oxfmt JS/TS config file prefix.
+const OXFMT_JS_CONFIG_PREFIX: &str = "oxfmt.config.";
+/// Vite+ config file prefix that may contain Oxfmt config under a `.fmt` field.
+const VITE_PLUS_JS_CONFIG_PREFIX: &str = "vite.config.";
+#[cfg(feature = "napi")]
+const VITE_PLUS_OXFMT_CONFIG_FIELD: &str = "fmt";
+
+/// Returns an iterator of all supported config file names, in priority order.
+pub fn all_config_file_names() -> impl Iterator<Item = String> {
+    let json = JSON_CONFIG_FILES.iter().map(|f| (*f).to_string());
+    let oxfmt_js = JS_CONFIG_EXTENSIONS.iter().map(|ext| format!("{OXFMT_JS_CONFIG_PREFIX}{ext}"));
+    let vite_plus =
+        JS_CONFIG_EXTENSIONS.iter().map(|ext| format!("{VITE_PLUS_JS_CONFIG_PREFIX}{ext}"));
+    json.chain(oxfmt_js).chain(vite_plus)
+}
 
 /// Resolve config file path from cwd and optional explicit path.
 pub fn resolve_oxfmtrc_path(cwd: &Path, config_path: Option<&Path>) -> Option<PathBuf> {
@@ -41,12 +49,12 @@ pub fn resolve_oxfmtrc_path(cwd: &Path, config_path: Option<&Path>) -> Option<Pa
         return Some(utils::normalize_relative_path(cwd, config_path));
     }
 
-    // If `--config` is not specified, search the nearest config file from cwd upwards
-    // Support JSON, JSONC, and JS/TS config files
-    // Prefer JSON/JSONC over JS/TS if both exist in the same directory
+    // If `--config` is not specified, search the nearest config file from cwd upwards.
+    // Support JSON, JSONC, and JS/TS config files.
+    // Prefer Oxfmt JSON/JSONC over JS/TS over Vite+ config if multiple exist in the same directory.
     cwd.ancestors().find_map(|dir| {
-        for filename in JSON_CONFIG_FILES.iter().chain(JS_CONFIG_FILES.iter()) {
-            let config_path = dir.join(filename);
+        for filename in all_config_file_names() {
+            let config_path = dir.join(&filename);
             if config_path.exists() {
                 return Some(config_path);
             }
@@ -230,39 +238,54 @@ impl ConfigResolver {
     ) -> Result<Self, String> {
         // Uses extension-based matching so that both auto-discovered files (e.g. `oxfmt.config.ts`)
         // and explicitly specified files (e.g. `--config ./my-config.ts`) are handled.
-        let is_js_config_path = |path: &Path| {
-            let Some(ext) = path.extension().and_then(|e| e.to_str()) else {
-                return false;
-            };
-            JS_CONFIG_FILES.iter().any(|f| f.ends_with(ext))
-        };
+        let is_js_config = oxfmtrc_path.is_some_and(|path| {
+            path.extension()
+                .and_then(|e| e.to_str())
+                .is_some_and(|ext| JS_CONFIG_EXTENSIONS.contains(&ext))
+        });
 
-        if let Some(path) = oxfmtrc_path
-            && is_js_config_path(path)
-        {
-            #[cfg(not(feature = "napi"))]
-            return Err(format!(
+        #[cfg(not(feature = "napi"))]
+        if is_js_config {
+            return Err(
                 "JS/TS config files are not supported in pure Rust CLI.\nUse JSON/JSONC instead."
-            ));
+                    .to_string(),
+            );
+        }
 
-            // Call `import(oxfmtrc_path)` via NAPI
-            #[cfg(feature = "napi")]
-            {
-                let raw_config = js_config_loader
-                    .expect("JS config loader must be set when `napi` feature is enabled")(
-                    path.to_string_lossy().into_owned(),
+        // Call `import(oxfmtrc_path)` via NAPI
+        #[cfg(feature = "napi")]
+        if let Some(path) = oxfmtrc_path
+            && is_js_config
+        {
+            let raw_config = js_config_loader
+                .expect("JS config loader must be set when `napi` feature is enabled")(
+                path.to_string_lossy().into_owned(),
+            )
+            .map_err(|_| {
+                format!(
+                    "{}\nEnsure the file has a valid default export of a JSON-serializable configuration object.",
+                    path.display()
                 )
-                .map_err(|_| {
-                    format!(
-                        "{}\nEnsure the file has a valid default export of a JSON-serializable configuration object.",
-                        path.display()
-                    )
-                })?;
-                let config_dir = path.parent().map(Path::to_path_buf);
-                let editorconfig = load_editorconfig(cwd, editorconfig_path)?;
+            })?;
+
+            // Vite+ config files (e.g. `vite.config.ts`),
+            // under a `.fmt` field instead of the default export directly.
+            let is_vite_plus = path
+                .file_name()
+                .and_then(|f| f.to_str())
+                .is_some_and(|name| name.starts_with(VITE_PLUS_JS_CONFIG_PREFIX));
+            let raw_config = if is_vite_plus {
+                raw_config.get(VITE_PLUS_OXFMT_CONFIG_FIELD).cloned().ok_or_else(|| {
+                    format!("{}\nExpected a `{VITE_PLUS_OXFMT_CONFIG_FIELD}` field in the default export.", path.display())
+                })?
+            } else {
+                raw_config
+            };
 
-                return Ok(Self::new(raw_config, config_dir, editorconfig));
-            }
+            let config_dir = path.parent().map(Path::to_path_buf);
+            let editorconfig = load_editorconfig(cwd, editorconfig_path)?;
+
+            return Ok(Self::new(raw_config, config_dir, editorconfig));
         }
 
         Self::from_json_config(cwd, oxfmtrc_path, editorconfig_path)

apps/oxfmt/src/core/mod.rs

@@ -9,13 +9,13 @@ mod external_formatter;
 #[cfg(feature = "napi")]
 mod js_config;
 
+#[cfg(feature = "napi")]
+pub use config::all_config_file_names;
 #[cfg(feature = "napi")]
 pub use config::resolve_options_from_value;
 pub use config::{
     ConfigResolver, ResolvedOptions, resolve_editorconfig_path, resolve_oxfmtrc_path,
 };
-#[cfg(feature = "napi")]
-pub use config::{JS_CONFIG_FILES, JSON_CONFIG_FILES};
 pub use format::{FormatResult, SourceFormatter};
 pub use support::FormatFileStrategy;
 

apps/oxfmt/src/lsp/server_formatter.rs

@@ -8,9 +8,8 @@ use oxc_data_structures::rope::{Rope, get_line_column};
 use oxc_language_server::{Capabilities, LanguageId, Tool, ToolBuilder, ToolRestartChanges};
 
 use crate::core::{
-    ConfigResolver, ExternalFormatter, FormatFileStrategy, FormatResult, JS_CONFIG_FILES,
-    JSON_CONFIG_FILES, JsConfigLoaderCb, SourceFormatter, resolve_editorconfig_path,
-    resolve_oxfmtrc_path, utils,
+    ConfigResolver, ExternalFormatter, FormatFileStrategy, FormatResult, JsConfigLoaderCb,
+    SourceFormatter, all_config_file_names, resolve_editorconfig_path, resolve_oxfmtrc_path, utils,
 };
 use crate::lsp::create_fake_file_path_from_language_id;
 use crate::lsp::options::FormatOptions as LSPFormatOptions;
@@ -234,11 +233,8 @@ impl Tool for ServerFormatter {
             if let Some(config_path) = options.config_path.as_ref().filter(|s| !s.is_empty()) {
                 vec![config_path.clone()]
             } else {
-                JSON_CONFIG_FILES
-                    .iter()
-                    .chain(JS_CONFIG_FILES.iter())
-                    .map(|file| (*file).to_string())
-                    .collect()
+                // TODO: This can be glob patterns?
+                all_config_file_names().collect()
             };
 
         patterns.push(".editorconfig".to_string());

apps/oxfmt/test/cli/vite_config/__snapshots__/vite_config.test.ts.snap

@@ -0,0 +1,49 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`vite_config > basic: reads fmt field from vite.config.ts 1`] = `
+"--------------------
+arguments: --check test.ts
+working directory: vite_config/fixtures/basic
+exit code: 1
+--- STDOUT ---------
+Checking formatting...
+
+test.ts (<variable>ms)
+
+Format issues found in above 1 files. Run without \`--check\` to fix.
+Finished in <variable>ms on 1 files using 1 threads.
+--- STDERR ---------
+
+--------------------"
+`;
+
+exports[`vite_config > error: no fmt field in vite.config.ts 1`] = `
+"--------------------
+arguments: --check test.ts
+working directory: vite_config/fixtures/error_no_fmt_field
+exit code: 1
+--- STDOUT ---------
+
+--- STDERR ---------
+Failed to load configuration file.
+<cwd>/vite.config.ts
+Expected a \`fmt\` field in the default export.
+--------------------"
+`;
+
+exports[`vite_config > priority: oxfmt.config.ts takes precedence over vite.config.ts 1`] = `
+"--------------------
+arguments: --check test.ts
+working directory: vite_config/fixtures/priority
+exit code: 1
+--- STDOUT ---------
+Checking formatting...
+
+test.ts (<variable>ms)
+
+Format issues found in above 1 files. Run without \`--check\` to fix.
+Finished in <variable>ms on 1 files using 1 threads.
+--- STDERR ---------
+
+--------------------"
+`;

apps/oxfmt/test/cli/vite_config/fixtures/basic/test.ts

@@ -0,0 +1 @@
+const a = 1;

apps/oxfmt/test/cli/vite_config/fixtures/basic/vite.config.ts

@@ -0,0 +1,5 @@
+export default {
+  fmt: {
+    semi: false,
+  },
+};

apps/oxfmt/test/cli/vite_config/fixtures/error_no_fmt_field/test.ts

@@ -0,0 +1 @@
+const a = 1;

apps/oxfmt/test/cli/vite_config/fixtures/error_no_fmt_field/vite.config.ts

@@ -0,0 +1,3 @@
+export default {
+  plugins: [],
+};

apps/oxfmt/test/cli/vite_config/fixtures/priority/oxfmt.config.ts

@@ -0,0 +1,3 @@
+export default {
+  semi: false,
+};

apps/oxfmt/test/cli/vite_config/fixtures/priority/test.ts

@@ -0,0 +1 @@
+const a = 1;

apps/oxfmt/test/cli/vite_config/fixtures/priority/vite.config.ts

@@ -0,0 +1,5 @@
+export default {
+  fmt: {
+    semi: true,
+  },
+};

apps/oxfmt/test/cli/vite_config/vite_config.test.ts

@@ -0,0 +1,27 @@
+import { describe, expect, it } from "vitest";
+import { join } from "node:path";
+import { runAndSnapshot } from "../utils";
+
+const fixturesDir = join(import.meta.dirname, "fixtures");
+
+describe("vite_config", () => {
+  it("basic: reads fmt field from vite.config.ts", async () => {
+    const cwd = join(fixturesDir, "basic");
+    const snapshot = await runAndSnapshot(cwd, [["--check", "test.ts"]]);
+    expect(snapshot).toMatchSnapshot();
+  });
+
+  it("error: no fmt field in vite.config.ts", async () => {
+    const cwd = join(fixturesDir, "error_no_fmt_field");
+    const snapshot = await runAndSnapshot(cwd, [["--check", "test.ts"]]);
+    expect(snapshot).toMatchSnapshot();
+  });
+
+  it("priority: oxfmt.config.ts takes precedence over vite.config.ts", async () => {
+    // `oxfmt.config.ts` has `semi: false`, `vite.config.ts` has `semi: true`
+    // oxfmt.config.ts should win, so `const a = 1;` (with semicolon) should be flagged
+    const cwd = join(fixturesDir, "priority");
+    const snapshot = await runAndSnapshot(cwd, [["--check", "test.ts"]]);
+    expect(snapshot).toMatchSnapshot();
+  });
+});

apps/oxfmt/test/lsp/format/__snapshots__/format.test.ts.snap

@@ -189,6 +189,18 @@ file://<fixture>/config-sort-tailwindcss/test.vue
 --------------------"
 `;
 
+exports[`LSP formatting > config options > should apply config from config-vite-semi/test.ts 1`] = `
+"--- URI -----------
+file://<fixture>/config-vite-semi/test.ts
+--- BEFORE ---------
+const x = 1;
+
+--- AFTER ----------
+const x = 1
+
+--------------------"
+`;
+
 exports[`LSP formatting > config options > should apply config from config-vue-indent/test.vue 1`] = `
 "--- URI -----------
 file://<fixture>/config-vue-indent/test.vue

apps/oxfmt/test/lsp/format/fixtures/config-vite-semi/test.ts

@@ -0,0 +1 @@
+const x = 1;

apps/oxfmt/test/lsp/format/fixtures/config-vite-semi/vite.config.ts

@@ -0,0 +1,5 @@
+export default {
+  fmt: {
+    semi: false,
+  },
+};

apps/oxfmt/test/lsp/format/format.test.ts

@@ -24,6 +24,7 @@ describe("LSP formatting", () => {
     it.each([
       ["config-semi/test.ts", "typescript"],
       ["config-js-semi/test.ts", "typescript"],
+      ["config-vite-semi/test.ts", "typescript"],
       ["config-no-sort-package-json/package.json", "json"],
       ["config-vue-indent/test.vue", "vue"],
       ["config-sort-imports/test.js", "javascript"],

apps/oxfmt/test/lsp/init/init.test.ts

@@ -27,6 +27,12 @@ describe("LSP initialization", () => {
         "oxfmt.config.js",
         "oxfmt.config.mjs",
         "oxfmt.config.cjs",
+        "vite.config.ts",
+        "vite.config.mts",
+        "vite.config.cts",
+        "vite.config.js",
+        "vite.config.mjs",
+        "vite.config.cjs",
         ".editorconfig",
       ],
     ],
@@ -41,6 +47,12 @@ describe("LSP initialization", () => {
         "oxfmt.config.js",
         "oxfmt.config.mjs",
         "oxfmt.config.cjs",
+        "vite.config.ts",
+        "vite.config.mts",
+        "vite.config.cts",
+        "vite.config.js",
+        "vite.config.mjs",
+        "vite.config.cjs",
         ".editorconfig",
       ],
     ],