vue - utils.js
exports:导出功能函数或变量
module.exports:默认导出{}
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module.exports 初始值为一个空对象 {}
exports 是指向的 module.exports 的引用
require() 返回的是 module.exports 而不是 exports
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关于module.exports和exports.js详情请查看:https://cnodejs.org/topic/5231a630101e574521e45ef8
1 'use strict' 2 // 路径 3 const path = require('path') 4 // 来自config/index.js 5 const config = require('../config') 6 7 const ExtractTextPlugin = require('extract-text-webpack-plugin') 8 // 来自package.json 9 const packageConfig = require('../package.json') 10 11 exports.assetsPath = function (_path) { 12 const assetsSubDirectory = process.env.NODE_ENV === 'production' 13 ? config.build.assetsSubDirectory 14 : config.dev.assetsSubDirectory 15 16 return path.posix.join(assetsSubDirectory, _path) 17 } 18 19 exports.cssLoaders = function (options) { 20 options = options || {} 21 22 const cssLoader = { 23 loader: 'css-loader', 24 options: { 25 sourceMap: options.sourceMap 26 } 27 } 28 29 const postcssLoader = { 30 loader: 'postcss-loader', 31 options: { 32 sourceMap: options.sourceMap 33 } 34 } 35 36 // 生成与extract文本插件一起使用的加载器字符串 37 function generateLoaders(loader, loaderOptions) { 38 const loaders = options.usePostCSS ? [cssLoader, postcssLoader] : [cssLoader] 39 40 if (loader) { 41 loaders.push({ 42 loader: loader + '-loader', 43 options: Object.assign({}, loaderOptions, { 44 sourceMap: options.sourceMap 45 }) 46 }) 47 } 48 49 //指定该选项时提取CSS 50 //(在生产构建期间就是这种情况) 51 if (options.extract) { 52 return ExtractTextPlugin.extract({ 53 use: loaders, 54 fallback: 'vue-style-loader' 55 }) 56 } else { 57 return ['vue-style-loader'].concat(loaders) 58 } 59 } 60 61 // https://vue-loader.vuejs.org/en/configurations/extract-css.html 62 return { 63 css: generateLoaders(), 64 postcss: generateLoaders(), 65 less: generateLoaders('less'), 66 sass: generateLoaders('sass', { indentedSyntax: true }), 67 scss: generateLoaders('sass'), 68 stylus: generateLoaders('stylus'), 69 styl: generateLoaders('stylus') 70 } 71 } 72 73 // 为单独样式文件生成加载器(.vue之外) 74 exports.styleLoaders = function (options) { 75 const output = [] 76 const loaders = exports.cssLoaders(options) 77 78 for (const extension in loaders) { 79 const loader = loaders[extension] 80 output.push({ 81 test: new RegExp('\\.' + extension + '$'), 82 use: loader 83 }) 84 } 85 86 return output 87 } 88 89 exports.createNotifierCallback = () => { 90 const notifier = require('node-notifier') 91 92 return (severity, errors) => { 93 if (severity !== 'error') return 94 95 const error = errors[0] 96 const filename = error.file && error.file.split('!').pop() 97 98 notifier.notify({ 99 title: packageConfig.name, 100 message: severity + ': ' + error.name, 101 subtitle: filename || '', 102 icon: path.join(__dirname, 'logo.png') 103 }) 104 } 105 }