fix(node): improve directory import error suggestion (#30619)

libs/node_resolver/errors.rs

@@ -892,13 +892,13 @@ impl NodeJsErrorCoded for ModuleNotFoundError {
   self.code(),
   dir_url,
   maybe_referrer.as_ref().map(|referrer| format!(" imported from '{}'", referrer)).unwrap_or_default(),
-  suggested_file_name.map(|file_name| format!("\nDid you mean to import {file_name} within the directory?")).unwrap_or_default(),
+  suggestion.as_ref().map(|suggestion| format!("\nDid you mean to import '{suggestion}'?")).unwrap_or_default(),
 )]
 #[property("code" = self.code())]
 pub struct UnsupportedDirImportError {
   pub dir_url: UrlOrPath,
   pub maybe_referrer: Option<UrlOrPath>,
-  pub suggested_file_name: Option<&'static str>,
+  pub suggestion: Option<String>,
 }
 
 impl NodeJsErrorCoded for UnsupportedDirImportError {

libs/node_resolver/resolution.rs

@@ -564,14 +564,12 @@ impl<
         if resolution_mode == ResolutionMode::Import
           && !self.resolution_config.bundle_mode
         {
-          let suggested_file_name = ["index.mjs", "index.js", "index.cjs"]
-            .into_iter()
-            .find(|e| self.sys.is_file(&path.join(e)));
+          let suggestion = self.directory_import_suggestion(&path);
           Err(
             UnsupportedDirImportError {
               dir_url: UrlOrPath::Path(path.into_owned()),
               maybe_referrer: maybe_referrer.map(|r| r.display()),
-              suggested_file_name,
+              suggestion,
             }
             .into(),
           )
@@ -662,6 +660,51 @@ impl<
     }
   }
 
+  fn directory_import_suggestion(
+    &self,
+    dir_import_path: &Path,
+  ) -> Option<String> {
+    let dir_index_paths = ["index.mjs", "index.js", "index.cjs"]
+      .into_iter()
+      .map(|file_name| dir_import_path.join(file_name));
+    let file_paths = [
+      with_known_extension(dir_import_path, "js"),
+      with_known_extension(dir_import_path, "mjs"),
+      with_known_extension(dir_import_path, "cjs"),
+    ];
+    dir_index_paths
+      .chain(file_paths)
+      .chain(
+        std::iter::once_with(|| {
+          // check if this directory has a package.json
+          let package_json_path = dir_import_path.join("package.json");
+          let pkg_json = self
+            .pkg_json_resolver
+            .load_package_json(&package_json_path)
+            .ok()??;
+          let main = pkg_json.main.as_ref()?;
+          Some(dir_import_path.join(main))
+        })
+        .flatten(),
+      )
+      .map(|p| deno_path_util::normalize_path(Cow::Owned(p)))
+      .find(|p| self.sys.is_file(p))
+      .and_then(|suggested_file_path| {
+        let pkg_json = self
+          .pkg_json_resolver
+          .get_closest_package_jsons(&suggested_file_path)
+          .filter_map(|pkg_json| pkg_json.ok())
+          .find(|p| p.name.is_some())?;
+        let pkg_name = pkg_json.name.as_ref()?;
+        let sub_path = suggested_file_path
+          .strip_prefix(pkg_json.dir_path())
+          .ok()?
+          .to_string_lossy()
+          .replace("\\", "/");
+        Some(format!("{}/{}", pkg_name, sub_path))
+      })
+  }
+
   pub fn resolve_package_subpath_from_deno_module(
     &self,
     package_dir: &Path,

tests/specs/node/esm_dir_import/dir_same_name_file/__test__.jsonc

@@ -0,0 +1,5 @@
+{
+  "args": "run main.ts",
+  "exitCode": 1,
+  "output": "error.out"
+}

tests/specs/node/esm_dir_import/dir_same_name_file/error.out

@@ -0,0 +1,3 @@
+error: [ERR_UNSUPPORTED_DIR_IMPORT] Directory import [WILDLINE]
+Did you mean to import 'package/dir.js'?
+    at [WILDLINE]

tests/specs/node/esm_dir_import/dir_same_name_file/main.ts

@@ -0,0 +1 @@
+import {} from "package/dir";

tests/specs/node/esm_dir_import/dir_same_name_file/node_modules/package/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "package"
+}

tests/specs/node/esm_dir_import/dir_same_name_file/package.json

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

tests/specs/node/esm_dir_import/index_js/folder_index_js.out

@@ -4,4 +4,4 @@ error: Could not resolve 'npm:@denotest/sub-folders@1.0.0/folder_index_js'
 
 Caused by:
     [ERR_UNSUPPORTED_DIR_IMPORT] Directory import 'file:///[WILDLINE]/folder_index_js' is not supported resolving ES modules imported from 'file:///[WILDLINE]/folder_index_js.ts'
-    Did you mean to import index.js within the directory?
+    Did you mean to import '@denotest/sub-folders/folder_index_js/index.js'?

tests/specs/node/esm_dir_import/package_json/__test__.jsonc

@@ -0,0 +1,5 @@
+{
+  "args": "run main.ts",
+  "exitCode": 1,
+  "output": "error.out"
+}

tests/specs/node/esm_dir_import/package_json/error.out

@@ -0,0 +1,3 @@
+error: [ERR_UNSUPPORTED_DIR_IMPORT] Directory import [WILDLINE]
+Did you mean to import 'fp-ts/lib/function.js'?
+    at [WILDLINE]

tests/specs/node/esm_dir_import/package_json/main.ts

@@ -0,0 +1 @@
+import {} from "fp-ts/function";

tests/specs/node/esm_dir_import/package_json/node_modules/fp-ts/function/package.json

@@ -0,0 +1,3 @@
+{
+  "main": "../lib/function.js"
+}

tests/specs/node/esm_dir_import/package_json/node_modules/fp-ts/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "fp-ts"
+}

tests/specs/node/esm_dir_import/package_json/package.json

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