feat: default to TS for file extension and support ext flag in more scenarios (#25472)

Closes #11220
Currently does lint, fmt, and repl

1 files changed, 8 insertions, 1 deletions

diff --git a/cli/tools/lint/linter.rs b/cli/tools/lint/linter.rs
index 777fe4d09..2c2bc43ac 100644
--- a/cli/tools/lint/linter.rs
+++ b/cli/tools/lint/linter.rs
@@ -94,9 +94,16 @@ impl CliLinter {
     &self,
     file_path: &Path,
     source_code: String,
+    ext: Option<&str>,
   ) -> Result<(ParsedSource, Vec<LintDiagnostic>), AnyError> {
     let specifier = specifier_from_file_path(file_path)?;
-    let media_type = MediaType::from_specifier(&specifier);
+    let media_type = if let Some(ext) = ext {
+      MediaType::from_str(&format!("placeholder.{ext}"))
+    } else if file_path.extension().is_none() {
+      MediaType::TypeScript
+    } else {
+      MediaType::from_specifier(&specifier)
+    };
 
     if self.fix {
       self.lint_file_and_fix(&specifier, media_type, source_code, file_path)