fix(typescript): normalize emittedFiles to prevent unrecoginized token

packages/typescript/src/index.ts

@@ -69,7 +69,7 @@ export default function typescript(options: RollupTypescriptOptions = {}): Plugi
             if (parsedOptions.options.composite || parsedOptions.options.incremental) {
               tsCache.cacheCode(fileName, data);
             }
-            emittedFiles.set(fileName, data);
+            emittedFiles.set(fileName.toLowerCase(), data);
           },
           status(diagnostic) {
             watchProgramHelper.handleStatus(diagnostic);

packages/typescript/src/outputFile.ts

@@ -41,8 +41,8 @@ export function getEmittedFile(
 ): string | undefined {
   let code: string | undefined;
   if (fileName) {
-    if (emittedFiles.has(fileName)) {
-      code = emittedFiles.get(fileName);
+    if (emittedFiles.has(fileName.toLowerCase())) {
+      code = emittedFiles.get(fileName.toLowerCase());
     } else {
       code = tsCache.getCached(fileName);
     }

packages/typescript/test/fixtures/caseTest/Main.ts

@@ -0,0 +1,3 @@
+const answer = 42;
+// eslint-disable-next-line no-console
+console.log(`the answer is ${answer}`);

packages/typescript/test/fixtures/caseTest/tsconfig.json

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

packages/typescript/test/test.js

@@ -1346,3 +1346,27 @@ test.serial('noForceEmit option defers to tsconfig.json for noEmit', async (t) =
   const originalCode = fs.readFileSync(path.join(__dirname, input), 'utf8');
   t.is(output[0].code, originalCode);
 });
+
+test.serial('incorrect file case still compiles', async (t) => {
+  const warnings = [];
+  const bundle = await rollup({
+    input: 'fixtures/caseTest/Main.ts',
+    plugins: [typescript({ tsconfig: 'fixtures/caseTest/tsconfig.json', target: 'es5' })],
+    onwarn(warning) {
+      warnings.push(warning);
+    }
+  });
+  // generate a single output bundle, in which case, declaration files were not correctly emitted
+  const output = await getCode(
+    bundle,
+    { format: 'es', file: 'fixtures/caseTest/dist/Main.js' },
+    true
+  );
+
+  t.deepEqual(
+    output.map((out) => out.fileName),
+    // no `main.d.ts`, main.js is passed through
+    ['Main.js']
+  );
+  t.is(warnings.length, 0);
+});