Merge pull request #5947 from anru/patch-3

Fixed missing iframe.html in output directory

lib/core/src/server/preview/iframe-webpack.config.js

@@ -37,7 +37,7 @@ export default ({
     devtool: '#cheap-module-source-map',
     entry: entries,
     output: {
-      path: path.join(process.cwd(), outputDir),
+      path: path.resolve(process.cwd(), outputDir),
       filename: '[name].[hash].bundle.js',
       publicPath: '',
     },