Fix iife extern and tests (#254)

Author: kristoferbaxter

src/options.ts

@@ -18,7 +18,7 @@ import { Transform } from './types';
 import { ModuleFormat, OutputOptions } from 'rollup';
 import { CompileOptions } from 'google-closure-compiler';
 import { sync } from 'temp-write';
-import { logSource } from './debug';
+import { log, logSource } from './debug';
 
 export const ERROR_WARNINGS_ENABLED_LANGUAGE_OUT_UNSPECIFIED =
   'Providing the warning_level=VERBOSE compile option also requires a valid language_out compile option.';
@@ -78,11 +78,13 @@ export const defaults = (
         .filter(Boolean)
         .concat(providedExterns)
     : providedExterns.length > 0
-      ? providedExterns
-      : '';
+    ? providedExterns
+    : '';
 
   if (typeof externs === 'string' && externs !== '') {
     logSource('externs', externs);
+  } else if (Array.isArray(externs)) {
+    log('externs', externs);
   }
 
   return {

src/transformers/iife.ts

@@ -18,10 +18,10 @@ import { Transform } from '../types';
 import { OutputOptions } from 'rollup';
 
 const HEADER = `/**
-* @fileoverview Externs built via derived configuration from Rollup or input code.
-* This extern contains the iife name so it does not get mangled at the top level.
-* @externs
-*/
+ * @fileoverview Externs built via derived configuration from Rollup or input code.
+ * This extern contains the iife name so it does not get mangled at the top level.
+ * @externs
+ */
 `;
 
 /**
@@ -35,7 +35,7 @@ export default class IifeTransform extends Transform {
 
   public extern(options: OutputOptions): string {
     if (options.format === 'iife' && options.name) {
-      return HEADER + `function ${options.name}(){};\n`;
+      return HEADER + `window['${options.name}'] = ${options.name};\n`;
     }
 
     return '';

test/iife/fixtures/iife.extern.js

@@ -3,4 +3,4 @@
  * This extern contains the iife name so it does not get mangled at the top level.
  * @externs
  */
-function wrapper(){};
+window['wrapper'] = wrapper;

test/iife/iife-wrapped-safely.test.js

@@ -33,12 +33,14 @@ test('generate extern for iife name', async t => {
   const transforms = createTransforms({});
   const options = defaults(outputOptions, [], transforms);
 
-  const contentMatch = options.externs.some(async externFilePath => {
+  for (const externFilePath of options.externs) {
     const fileContent = await fsPromises.readFile(externFilePath, 'utf8');
-    return fileContent === externFixtureContent;
-  });
-
-  t.is(contentMatch, true);
+    if (fileContent === externFixtureContent) {
+      t.pass();
+      return;
+    }
+  }
+  t.fail('None of the externs match the expected format');
 });
 
 generator('iife', 'iife-wrapped-safely', undefined, ['iife'], undefined, 'wrapper');