feat: add Resolver::resolve_tsconfig API (#312)

closes #289

src/lib.rs

@@ -177,6 +177,22 @@ impl<Fs: FileSystem> ResolverGeneric<Fs> {
         self.resolve_tracing(directory.as_ref(), specifier, &mut ctx)
     }
 
+    /// Resolve `tsconfig`.
+    ///
+    /// The path can be:
+    ///
+    /// * Path to a file with `.json` extension.
+    /// * Path to a file without `.json` extension, `.json` will be appended to filename.
+    /// * Path to a directory, where the filename is defaulted to `tsconfig.json`
+    ///
+    /// # Errors
+    ///
+    /// * See [ResolveError]
+    pub fn resolve_tsconfig<P: AsRef<Path>>(&self, path: P) -> Result<Arc<TsConfig>, ResolveError> {
+        let path = path.as_ref();
+        self.load_tsconfig(true, path, &TsconfigReferences::Auto)
+    }
+
     /// Resolve `specifier` at absolute `path` with [ResolveContext]
     ///
     /// # Errors
@@ -1114,30 +1130,6 @@ impl<Fs: FileSystem> ResolverGeneric<Fs> {
         None
     }
 
-    fn load_tsconfig_paths(
-        &self,
-        cached_path: &CachedPath,
-        specifier: &str,
-        ctx: &mut Ctx,
-    ) -> ResolveResult {
-        let Some(tsconfig_options) = &self.options.tsconfig else {
-            return Ok(None);
-        };
-        let tsconfig = self.load_tsconfig(
-            /* root */ true,
-            &tsconfig_options.config_file,
-            &tsconfig_options.references,
-        )?;
-        let paths = tsconfig.resolve(cached_path.path(), specifier);
-        for path in paths {
-            let cached_path = self.cache.value(&path);
-            if let Ok(path) = self.require_relative(&cached_path, ".", ctx) {
-                return Ok(Some(path));
-            }
-        }
-        Ok(None)
-    }
-
     fn load_tsconfig(
         &self,
         root: bool,
@@ -1205,6 +1197,30 @@ impl<Fs: FileSystem> ResolverGeneric<Fs> {
         })
     }
 
+    fn load_tsconfig_paths(
+        &self,
+        cached_path: &CachedPath,
+        specifier: &str,
+        ctx: &mut Ctx,
+    ) -> ResolveResult {
+        let Some(tsconfig_options) = &self.options.tsconfig else {
+            return Ok(None);
+        };
+        let tsconfig = self.load_tsconfig(
+            /* root */ true,
+            &tsconfig_options.config_file,
+            &tsconfig_options.references,
+        )?;
+        let paths = tsconfig.resolve(cached_path.path(), specifier);
+        for path in paths {
+            let cached_path = self.cache.value(&path);
+            if let Ok(path) = self.require_relative(&cached_path, ".", ctx) {
+                return Ok(Some(path));
+            }
+        }
+        Ok(None)
+    }
+
     fn get_extended_tsconfig_path(
         &self,
         directory: &CachedPath,

src/tsconfig.rs

@@ -25,11 +25,11 @@ pub struct TsConfig {
     /// Whether this is the caller tsconfig.
     /// Used for final template variable substitution when all configs are extended and merged.
     #[serde(skip)]
-    root: bool,
+    pub root: bool,
 
     /// Path to `tsconfig.json`. Contains the `tsconfig.json` filename.
     #[serde(skip)]
-    pub(crate) path: PathBuf,
+    pub path: PathBuf,
 
     #[serde(default)]
     pub extends: Option<ExtendsField>,
@@ -48,10 +48,10 @@ pub struct TsConfig {
 #[derive(Debug, Default, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct CompilerOptions {
-    base_url: Option<PathBuf>,
+    pub base_url: Option<PathBuf>,
 
     /// Path aliases
-    paths: Option<CompilerOptionsPathsMap>,
+    pub paths: Option<CompilerOptionsPathsMap>,
 
     /// The actual base for where path aliases are resolved from.
     #[serde(skip)]
@@ -73,7 +73,21 @@ pub struct ProjectReference {
 }
 
 impl TsConfig {
-    pub fn parse(root: bool, path: &Path, json: &mut str) -> Result<Self, serde_json::Error> {
+    /// Directory to `tsconfig.json`
+    ///
+    /// # Panics
+    ///
+    /// * When the `tsconfig.json` path is misconfigured.
+    pub fn directory(&self) -> &Path {
+        debug_assert!(self.path.file_name().is_some());
+        self.path.parent().unwrap()
+    }
+
+    pub(crate) fn parse(
+        root: bool,
+        path: &Path,
+        json: &mut str,
+    ) -> Result<Self, serde_json::Error> {
         _ = json_strip_comments::strip(json);
         let mut tsconfig: Self = serde_json::from_str(json)?;
         tsconfig.root = root;
@@ -89,7 +103,7 @@ impl TsConfig {
         Ok(tsconfig)
     }
 
-    pub fn build(mut self) -> Self {
+    pub(crate) fn build(mut self) -> Self {
         if self.root {
             let dir = self.directory().to_path_buf();
             // Substitute template variable in `tsconfig.compilerOptions.paths`
@@ -104,17 +118,7 @@ impl TsConfig {
         self
     }
 
-    /// Directory to `tsconfig.json`
-    ///
-    /// # Panics
-    ///
-    /// * When the `tsconfig.json` path is misconfigured.
-    pub fn directory(&self) -> &Path {
-        debug_assert!(self.path.file_name().is_some());
-        self.path.parent().unwrap()
-    }
-
-    pub fn extend_tsconfig(&mut self, tsconfig: &Self) {
+    pub(crate) fn extend_tsconfig(&mut self, tsconfig: &Self) {
         let compiler_options = &mut self.compiler_options;
         if compiler_options.paths.is_none() {
             compiler_options.paths_base = compiler_options
@@ -128,7 +132,7 @@ impl TsConfig {
         }
     }
 
-    pub fn resolve(&self, path: &Path, specifier: &str) -> Vec<PathBuf> {
+    pub(crate) fn resolve(&self, path: &Path, specifier: &str) -> Vec<PathBuf> {
         if path.starts_with(self.base_path()) {
             let paths = self.resolve_path_alias(specifier);
             if !paths.is_empty() {
@@ -145,7 +149,7 @@ impl TsConfig {
 
     // Copied from parcel
     // <https://github.com/parcel-bundler/parcel/blob/b6224fd519f95e68d8b93ba90376fd94c8b76e69/packages/utils/node-resolver-rs/src/tsconfig.rs#L93>
-    pub fn resolve_path_alias(&self, specifier: &str) -> Vec<PathBuf> {
+    pub(crate) fn resolve_path_alias(&self, specifier: &str) -> Vec<PathBuf> {
         if specifier.starts_with(['/', '.']) {
             return vec![];
         }

tests/integration_test.rs

@@ -41,6 +41,14 @@ fn package_json() {
     assert!(package_json.side_effects.as_ref().unwrap().is_object());
 }
 
+#[test]
+fn tsconfig() {
+    let resolver = Resolver::new(ResolveOptions::default());
+    let tsconfig = resolver.resolve_tsconfig("./tests").unwrap();
+    assert!(tsconfig.root);
+    assert_eq!(tsconfig.path, PathBuf::from("./tests/tsconfig.json"));
+}
+
 #[cfg(feature = "package_json_raw_json_api")]
 #[test]
 fn package_json_raw_json_api() {

tests/tsconfig.json

@@ -0,0 +1,2 @@
+{
+}