[1461] webpackChunkName get undefined

1. set nuxt.config.js

filenames: { chunk: '[name].[chunkhash].js' }

2. my directory like this picture

   <img width="146" alt="2017-08-24 3 35 06" src="https://user-images.githubusercontent.com/5194326/29634710-47e24a4c-887d-11e7-9408-56aee9c728f2.png">

3. npm run build

   then i got an undefined.chunkhash.js file in .nuxt/dist/pages directory

   i find it in Generating routes

   <img width="705" alt="2017-08-24 3 38 38" src="https://user-images.githubusercontent.com/5194326/29634983-302b4358-887e-11e7-879e-c54b85f41a74.png">

   is a bug?

   in code source /lib/common/utils.js .lines 189, here is

   route.name = route.name.replace(/-index$/, '')

   why do this?

   my english is poor，sorry