works with transform-decorators-legacy (#18)

package.json

@@ -28,6 +28,7 @@
     "rollup-pluginutils": "^1.1.0"
   },
   "devDependencies": {
+    "babel-plugin-transform-decorators-legacy": "^1.3.4",
     "babel-preset-es2015": "^6.1.18",
     "babel-preset-es2015-rollup": "^1.0.0",
     "babel-register": "^6.3.13",

src/index.js

@@ -4,7 +4,7 @@ import { createFilter } from 'rollup-pluginutils';
 function preflightCheck ( localOpts ) {
 	var check = transform( 'export default class Foo {}', localOpts ).code;
 	if ( ~check.indexOf( 'function _classCallCheck' ) ) throw new Error( 'External helpers are not enabled. Please add the "external-helpers-2" plugin or use the "es2015-rollup" preset. See https://github.com/rollup/rollup-plugin-babel#TK for more information' );
-	if ( !~check.indexOf( 'export default' ) ) throw new Error( 'It looks like your Babel configuration specifies a module transformer. Please disable it. If you\'re using the "es2015" preset, consider using "es2015-rollup" instead. See https://github.com/rollup/rollup-plugin-babel#TK for more information' );
+	if ( !~check.indexOf( 'export default' ) && !~check.indexOf( 'export { Foo as default }' ) ) throw new Error( 'It looks like your Babel configuration specifies a module transformer. Please disable it. If you\'re using the "es2015" preset, consider using "es2015-rollup" instead. See https://github.com/rollup/rollup-plugin-babel#TK for more information' );
 }
 
 function assign ( target, source ) {

test/samples/transform-decorators-legacy/.babelrc

@@ -0,0 +1,4 @@
+{
+	"presets": [ "es2015-rollup" ],
+	"plugins": [ "transform-decorators-legacy" ]
+}

test/samples/transform-decorators-legacy/main.js

@@ -0,0 +1 @@
+export default 42;

test/test.js

@@ -106,6 +106,13 @@ describe( 'rollup-plugin-babel', function () {
 		});
 	});
 
+	it( 'works with transform-decorators-legacy (#18)', function () {
+		return rollup.rollup({
+			entry: 'samples/transform-decorators-legacy/main.js',
+			plugins: [ babelPlugin() ]
+		});
+	});
+
 	it( 'checks config per-file', function () {
 		return rollup.rollup({
 			entry: 'samples/checks/main.js',