Set broccoli-typescript-compiler tsconfig options.

Author: chriskrycho

lib/typescript-preprocessor.js

@@ -24,7 +24,13 @@ class TypeScriptPreprocessor {
       annotation: 'TS files',
     });
 
-    const ts = tsc(tsFiles);
+    const ts = tsc(tsFiles, {
+      annotation: 'Compiled TS files',
+      compilerOptions: {
+        allowJs: false, // don't compile JS here; let Babel manage that
+        noEmit: false, // we *must* emit for Broccoli to do its thing
+      },
+    });
 
     // Put everything together.
     return new MergeTrees([js, ts], {