feat(oxfmt): Support formatting JSON files

apps/oxfmt/Cargo.toml

@@ -38,6 +38,7 @@ bpaf = { workspace = true, features = ["autocomplete", "bright-color", "derive"]
 cow-utils = { workspace = true }
 ignore = { workspace = true, features = ["simd-accel"] }
 miette = { workspace = true }
+phf = { workspace = true, features = ["macros"] }
 rayon = { workspace = true }
 simdutf8 = { workspace = true }
 tokio = { workspace = true, features = ["rt-multi-thread", "io-std", "macros"] }

apps/oxfmt/src/cli/walk.rs

@@ -222,13 +222,13 @@ impl ignore::ParallelVisitor for WalkVisitor {
                 // Use `is_file()` to detect symlinks to the directory named `.js`
                 #[expect(clippy::filetype_is_file)]
                 if file_type.is_file() {
-                    let path = entry.path();
                     // Determine this file should be handled or NOT
                     // Tier 1 = `.js`, `.tsx`, etc: JS/TS files supported by `oxc_formatter`
                     // Tier 2 = `.html`, `.json`, etc: Other files supported by Prettier
                     // (Tier 3 = `.astro`, `.svelte`, etc: Other files supported by Prettier plugins)
                     // Tier 4 = everything else: Not handled
-                    let Ok(format_file_source) = FormatFileSource::try_from(path) else {
+                    let Ok(format_file_source) = FormatFileSource::try_from(entry.into_path())
+                    else {
                         return ignore::WalkState::Continue;
                     };
 

apps/oxfmt/src/core/support.rs

@@ -1,5 +1,7 @@
 use std::path::{Path, PathBuf};
 
+use phf::phf_set;
+
 use oxc_formatter::get_supported_source_type;
 use oxc_span::SourceType;
 
@@ -8,30 +10,25 @@ pub enum FormatFileSource {
         path: PathBuf,
         source_type: SourceType,
     },
-    #[expect(dead_code)]
     ExternalFormatter {
         path: PathBuf,
-        parser_name: String,
+        #[cfg_attr(not(feature = "napi"), expect(dead_code))]
+        parser_name: &'static str,
     },
 }
 
-impl TryFrom<&Path> for FormatFileSource {
+impl TryFrom<PathBuf> for FormatFileSource {
     type Error = ();
 
-    fn try_from(path: &Path) -> Result<Self, Self::Error> {
+    fn try_from(path: PathBuf) -> Result<Self, Self::Error> {
         // TODO: This logic should(can) move to this file, after LSP support is also moved here.
-        if let Some(source_type) = get_supported_source_type(path) {
-            return Ok(Self::OxcFormatter { path: path.to_path_buf(), source_type });
+        if let Some(source_type) = get_supported_source_type(&path) {
+            return Ok(Self::OxcFormatter { path, source_type });
         }
 
-        // TODO: Support more files with `ExternalFormatter`
-        // - JSON
-        // - HTML(include .vue)
-        // - CSS
-        // - GraphQL
-        // - Markdown
-        // - YAML
-        // - Handlebars
+        if let Some(parser_name) = get_external_parser_name(&path) {
+            return Ok(Self::ExternalFormatter { path, parser_name });
+        }
 
         Err(())
     }
@@ -44,3 +41,206 @@ impl FormatFileSource {
         }
     }
 }
+
+// ---
+
+/// Returns the Prettier parser name for file at `path`, if supported.
+/// See also `prettier --support-info | jq '.languages[]'`
+/// NOTE: The order matters: more specific matches (like `package.json`) must come before generic ones.
+fn get_external_parser_name(path: &Path) -> Option<&'static str> {
+    let file_name = path.file_name()?.to_str()?;
+    let extension = path.extension().and_then(|ext| ext.to_str());
+
+    // O(1) file name check goes first
+    if JSON_STRINGIFY_FILENAMES.contains(file_name) || extension == Some("importmap") {
+        return Some("json-stringify");
+    }
+    if JSON_FILENAMES.contains(file_name) {
+        return Some("json");
+    }
+
+    // Then, check by extension
+    if (file_name.starts_with("tsconfig.") || file_name.starts_with("jsconfig."))
+        && extension == Some("json")
+    {
+        return Some("jsonc");
+    }
+    if let Some(ext) = extension
+        && JSON_EXTENSIONS.contains(ext)
+    {
+        return Some("json");
+    }
+    if let Some(ext) = extension
+        && JSONC_EXTENSIONS.contains(ext)
+    {
+        return Some("jsonc");
+    }
+    if extension == Some("json5") {
+        return Some("json5");
+    }
+
+    // TODO: Support more default supported file types
+    // {
+    //   "extensions": [".html", ".hta", ".htm", ".html.hl", ".inc", ".xht", ".xhtml"],
+    //   "name": "HTML",
+    //   "parsers": ["html"]
+    // },
+    // {
+    //   "extensions": [".mjml"],
+    //   "name": "MJML",
+    //   "parsers": ["mjml"]
+    // },
+    // {
+    //   "extensions": [".component.html"],
+    //   "name": "Angular",
+    //   "parsers": ["angular"]
+    // },
+    // {
+    //   "extensions": [".vue"],
+    //   "name": "Vue",
+    //   "parsers": ["vue"]
+    // },
+    //
+    // {
+    //   "extensions": [".css", ".wxss"],
+    //   "name": "CSS",
+    //   "parsers": ["css"]
+    // },
+    // {
+    //   "extensions": [".less"],
+    //   "name": "Less",
+    //   "parsers": ["less"]
+    // },
+    // {
+    //   "extensions": [".pcss", ".postcss"],
+    //   "group": "CSS",
+    //   "name": "PostCSS",
+    //   "parsers": ["css"]
+    // },
+    // {
+    //   "extensions": [".scss"],
+    //   "name": "SCSS",
+    //   "parsers": ["scss"]
+    // },
+    //
+    // {
+    //   "extensions": [".graphql", ".gql", ".graphqls"],
+    //   "name": "GraphQL",
+    //   "parsers": ["graphql"]
+    // },
+    //
+    // {
+    //   "extensions": [".handlebars", ".hbs"],
+    //   "name": "Handlebars",
+    //   "parsers": ["glimmer"]
+    // },
+    //
+    // {
+    //   "extensions": [".md", ".livemd", ".markdown", ".mdown", ".mdwn", ".mkd", ".mkdn", ".mkdown", ".ronn", ".scd", ".workbook"],
+    //   "filenames": ["contents.lr", "README"],
+    //   "name": "Markdown",
+    //   "parsers": ["markdown"]
+    // },
+    // {
+    //   "extensions": [".mdx"],
+    //   "name": "MDX",
+    //   "parsers": ["mdx"]
+    // },
+
+    None
+}
+
+static JSON_STRINGIFY_FILENAMES: phf::Set<&'static str> = phf_set! {
+    "package.json",
+    "package-lock.json",
+    "composer.json",
+};
+
+static JSON_EXTENSIONS: phf::Set<&'static str> = phf_set! {
+    "json",
+    "4DForm",
+    "4DProject",
+    "avsc",
+    "geojson",
+    "gltf",
+    "har",
+    "ice",
+    "JSON-tmLanguage",
+    "json.example",
+    "mcmeta",
+    "sarif",
+    "tact",
+    "tfstate",
+    "tfstate.backup",
+    "topojson",
+    "webapp",
+    "webmanifest",
+    "yy",
+    "yyp",
+};
+
+static JSON_FILENAMES: phf::Set<&'static str> = phf_set! {
+    ".all-contributorsrc",
+    ".arcconfig",
+    ".auto-changelog",
+    ".c8rc",
+    ".htmlhintrc",
+    ".imgbotconfig",
+    ".nycrc",
+    ".tern-config",
+    ".tern-project",
+    ".watchmanconfig",
+    ".babelrc",
+    ".jscsrc",
+    ".jshintrc",
+    ".jslintrc",
+    ".swcrc",
+};
+
+static JSONC_EXTENSIONS: phf::Set<&'static str> = phf_set! {
+    "jsonc",
+    "code-snippets",
+    "code-workspace",
+    "sublime-build",
+    "sublime-color-scheme",
+    "sublime-commands",
+    "sublime-completions",
+    "sublime-keymap",
+    "sublime-macro",
+    "sublime-menu",
+    "sublime-mousemap",
+    "sublime-project",
+    "sublime-settings",
+    "sublime-theme",
+    "sublime-workspace",
+    "sublime_metrics",
+    "sublime_session",
+};
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::path::Path;
+
+    #[test]
+    fn test_get_external_parser_name() {
+        let test_cases = vec![
+            ("package.json", Some("json-stringify")),
+            ("package-lock.json", Some("json-stringify")),
+            ("config.importmap", Some("json-stringify")),
+            ("tsconfig.json", Some("jsonc")),
+            ("jsconfig.dev.json", Some("jsonc")),
+            ("data.json", Some("json")),
+            ("schema.avsc", Some("json")),
+            ("config.code-workspace", Some("jsonc")),
+            ("unknown.txt", None),
+            ("prof.png", None),
+            ("foo", None),
+        ];
+
+        for (file_name, expected) in test_cases {
+            let result = get_external_parser_name(Path::new(file_name));
+            assert_eq!(result, expected, "`{file_name}` should be parsed as {expected:?}");
+        }
+    }
+}

apps/oxfmt/test/__snapshots__/config_file.test.ts.snap

@@ -2,7 +2,7 @@
 
 exports[`config_file > auto discovery > nested 1`] = `
 "--------------------
-arguments: --check
+arguments: --check !*.{json,jsonc}
 working directory: fixtures/config_file/nested
 exit code: 1
 --- STDOUT ---------
@@ -19,7 +19,7 @@ Finished in <variable>ms on 1 files using 1 threads.
 
 exports[`config_file > auto discovery > nested_deep 1`] = `
 "--------------------
-arguments: --check
+arguments: --check !*.{json,jsonc}
 working directory: fixtures/config_file/nested/deep
 exit code: 1
 --- STDOUT ---------
@@ -36,7 +36,7 @@ Finished in <variable>ms on 1 files using 1 threads.
 
 exports[`config_file > auto discovery > root 1`] = `
 "--------------------
-arguments: --check
+arguments: --check !*.{json,jsonc}
 working directory: fixtures/config_file
 exit code: 1
 --- STDOUT ---------
@@ -53,7 +53,7 @@ Finished in <variable>ms on 1 files using 1 threads.
 
 exports[`config_file > explicit config 1`] = `
 "--------------------
-arguments: --check --config ./fmt.json
+arguments: --check !*.{json,jsonc} --config ./fmt.json
 working directory: fixtures/config_file
 exit code: 1
 --- STDOUT ---------
@@ -67,7 +67,7 @@ Finished in <variable>ms on 1 files using 1 threads.
 
 --------------------
 --------------------
-arguments: --check --config ./fmt.jsonc
+arguments: --check !*.{json,jsonc} --config ./fmt.jsonc
 working directory: fixtures/config_file
 exit code: 1
 --- STDOUT ---------

apps/oxfmt/test/__snapshots__/config_ignore_patterns.test.ts.snap

@@ -4,21 +4,25 @@ exports[`config_ignore_patterns > should respect ignorePatterns in config 1`] =
 "--------------------
 arguments: --check
 working directory: fixtures/config_ignore_patterns
-exit code: 1
+exit code: 0
 --- STDOUT ---------
 Checking formatting...
 
+All matched files use the correct format.
+Finished in <variable>ms on 2 files using 1 threads.
 --- STDERR ---------
-Expected at least one target file
+
 --------------------
 --------------------
 arguments: --check --config fmtrc.jsonc
 working directory: fixtures/config_ignore_patterns
-exit code: 1
+exit code: 0
 --- STDOUT ---------
 Checking formatting...
 
+All matched files use the correct format.
+Finished in <variable>ms on 2 files using 1 threads.
 --- STDERR ---------
-Expected at least one target file
+
 --------------------"
 `;