fix: transform code for code coverage async if possible (#11852)

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 ### Fixes
 
+- `[@jest/reporters]` Use async transform if available to transform files with no coverage ([#11852](https://github.com/facebook/jest/pull/11852))
+
 ### Chore & Maintenance
 
 ### Performance

packages/jest-reporters/src/generateEmptyCoverage.ts

@@ -69,13 +69,17 @@ export default async function (
     const scriptTransformer = await createScriptTransformer(config);
 
     // Transform file with instrumentation to make sure initial coverage data is well mapped to original code.
-    const {code} = scriptTransformer.transformSource(filename, source, {
-      instrument: true,
-      supportsDynamicImport: true,
-      supportsExportNamespaceFrom: true,
-      supportsStaticESM: true,
-      supportsTopLevelAwait: true,
-    });
+    const {code} = await scriptTransformer.transformSourceAsync(
+      filename,
+      source,
+      {
+        instrument: true,
+        supportsDynamicImport: true,
+        supportsExportNamespaceFrom: true,
+        supportsStaticESM: true,
+        supportsTopLevelAwait: true,
+      },
+    );
     // TODO: consider passing AST
     const extracted = readInitialCoverage(code);
     // Check extracted initial coverage is not null, this can happen when using /* istanbul ignore file */