如何在vue中全局引入stylus文件的公共变量

// generate loader string to be used with extract text plugin
  function generateLoaders (loader, loaderOptions) {
    const loaders = options.usePostCSS ? [cssLoader, postcssLoader] : [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)
    }
  }
   var stylusOptions = {
        import: [
            path.join(__dirname, "../src/assets/css/public/var.styl"), // 全局变量文件 文件后缀名为.styl
        ]
    }
// https://vue-loader.vuejs.org/en/configurations/extract-css.html
  return {
    css: generateLoaders(),
    postcss: generateLoaders(),
    less: generateLoaders(‘less‘),
    sass: generateLoaders(‘sass‘, { indentedSyntax: true }),
    scss: generateLoaders(‘sass‘),
    stylus: generateLoaders(‘stylus‘,stylusOptions),
    styl: generateLoaders(‘stylus‘,stylusOptions)
  }