webpack alias 设置

function resolve (dir) {
  return path.join(__dirname, '..', dir)
}

resolve: {
    extensions: ['.js', '.vue', '.json','.styl'],
    alias: {
      'vue$': 'vue/dist/vue.esm.js',
      '@': resolve('src'),
      // '%': resolve('src/components')
      'components': path.resolve(__dirname, '../src/components')
    }
  },
import Vue from 'vue'
import Router from 'vue-router'
// import Header from '@/components/Header'
import Rating from 'components/rating'
// import Head from '../components/header'
// import Head from '%/header'
import Sell from 'components/sell'
import Detail from 'components/detail'