在VUE中怎么全局引入sass文件

在使用vue开发SPA应用中，我们经常需要在一个或多个scss文件中定义公共变量或者mixin亦或是很多通用的function，而且不希望在每个vue文件中都去@import，针对这种情况，可以使用下面的方法添加全局引入的sass文件，使这些样式或者方法可以被打包到全局的样式文件中。

1. 添加依赖

   npm install sass-resources-loader --save-dev

2. 修改build/utils.js

   'use strict'
   const path = require('path')
   const config = require('../config')
   const ExtractTextPlugin = require('extract-text-webpack-plugin')
   
   exports.assetsPath = function (_path) {
     const assetsSubDirectory = process.env.NODE_ENV === 'production'
    ? config.build.assetsSubDirectory
    : config.dev.assetsSubDirectory
     return path.posix.join(assetsSubDirectory, _path)
   }
   
   exports.cssLoaders = function (options) {
     options = options || {}
   
     const cssLoader = {
    loader: 'css-loader',
    options: {
      minimize: process.env.NODE_ENV === 'production',
      sourceMap: options.sourceMap
    }
     }
   
     // generate loader string to be used with extract text plugin
     function generateLoaders (loader, loaderOptions) {
    const loaders = [cssLoader]
    if (loader) {
      loaders.push({
        loader: loader + '-loader',
        options: Object.assign({}, loaderOptions, {
          sourceMap: options.sourceMap
        })
      })
    }
   
    // Extract CSS when that option is specified
    // (which is the case during production build)
    if (options.extract) {
      return ExtractTextPlugin.extract({
        use: loaders,
        fallback: 'vue-style-loader'
      })
    } else {
      return ['vue-style-loader'].concat(loaders)
    }
     }
     // 引入sass全局变量，mixin，function等
     function resolveResouce(name) {
    return path.resolve(__dirname, '../src/assets/style/' + name);
     }
     function generateSassResourceLoader() {
    var loaders = [
      cssLoader,
   // 'postcss-loader',
       'sass-loader',
       {
         loader: 'sass-resources-loader',
         options: {
           // it need a absolute path
           resources: [
             resolveResouce('reset.scss'),
             resolveResouce('var.scss'),
             resolveResouce('common.scss')
           ]
         }
       }
    ];
    if (options.extract) {
       return ExtractTextPlugin.extract({
         use: loaders,
         fallback: 'vue-style-loader'
       })
    } else {
      return ['vue-style-loader'].concat(loaders)
    }
     }
     // https://vue-loader.vuejs.org/en/configurations/extract-css.html
     // return部分加入上面的loader
     return {
    css: generateLoaders(),
    postcss: generateLoaders(),
    less: generateLoaders('less'),
    sass: generateSassResourceLoader(),
    scss: generateSassResourceLoader(),
    stylus: generateLoaders('stylus'),
    styl: generateLoaders('stylus')
     }
   }
   
   // Generate loaders for standalone style files (outside of .vue)
   exports.styleLoaders = function (options) {
     const output = []
     const loaders = exports.cssLoaders(options)
     for (const extension in loaders) {
    const loader = loaders[extension]
    output.push({
      test: new RegExp('\\.' + extension + '$'),
      use: loader
    })
     }
     return output
   }