test(typescript): close bundle in new watch-mode transformer test; refactor customTransformers for clearer lazy initialization

Author: CharlieHelps

packages/typescript/src/customTransformers.ts

@@ -35,21 +35,19 @@ export function mergeTransformers(
 
         if ('type' in transformer) {
           if (typeof transformer.factory === 'function') {
-            // Allow custom factories to grab the extra information required
-            program = program || builder.getProgram();
-
             let factory: ReturnType<typeof transformer.factory>;
 
             if (transformer.type === 'program') {
-              program = program || builder.getProgram();
-
+              const currentProgram = program ?? builder.getProgram();
               // Pass a getter so transformers can access the latest Program in watch mode
-              factory = transformer.factory(program, () => builder.getProgram());
+              factory = transformer.factory(currentProgram, () => builder.getProgram());
+              program = currentProgram;
             } else {
-              program = program || builder.getProgram();
-              typeChecker = typeChecker || program.getTypeChecker();
-
-              factory = transformer.factory(typeChecker);
+              const currentProgram = program ?? builder.getProgram();
+              const currentTypeChecker = typeChecker ?? currentProgram.getTypeChecker();
+              factory = transformer.factory(currentTypeChecker);
+              program = currentProgram;
+              typeChecker = currentTypeChecker;
             }
 
             // Forward the requested reference to the custom transformer factory

packages/typescript/test/test.js

@@ -1764,11 +1764,14 @@ test.serial(
       onwarn
     });
 
-    await getCode(bundle, { format: 'esm', dir: dirName }, true);
-
-    t.deepEqual(observations, [
-      { p: 'one', gp: 'one' },
-      { p: 'two', gp: 'two' }
-    ]);
+    try {
+      await getCode(bundle, { format: 'esm', dir: dirName }, true);
+      t.deepEqual(observations, [
+        { p: 'one', gp: 'one' },
+        { p: 'two', gp: 'two' }
+      ]);
+    } finally {
+      await bundle.close();
+    }
   }
 );