refactor: Use const/let instead of var with strict mode (#801)

Author: sudo-suhas

docs/backend.md

@@ -6,7 +6,8 @@ Let's take a look at the default `config/index.js`:
 
 ``` js
 // config/index.js
-var path = require('path')
+'use strict'
+const path = require('path')
 
 module.exports = {
   build: {

docs/prerender.md

@@ -14,7 +14,7 @@ npm install --save-dev prerender-spa-plugin
 
 ```js
 // This line should go at the top of the file where other 'imports' live in
-var PrerenderSpaPlugin = require('prerender-spa-plugin')
+const PrerenderSpaPlugin = require('prerender-spa-plugin')
 ```
 
 3. Configure it in the `plugins` array (also in **build/webpack.prod.conf.js**):

template/build/build.js

@@ -1,16 +1,17 @@
+'use strict'
 require('./check-versions')()
 
 process.env.NODE_ENV = 'production'
 
-var ora = require('ora')
-var rm = require('rimraf')
-var path = require('path')
-var chalk = require('chalk')
-var webpack = require('webpack')
-var config = require('../config')
-var webpackConfig = require('./webpack.prod.conf')
+const ora = require('ora')
+const rm = require('rimraf')
+const path = require('path')
+const chalk = require('chalk')
+const webpack = require('webpack')
+const config = require('../config')
+const webpackConfig = require('./webpack.prod.conf')
 
-var spinner = ora('building for production...')
+const spinner = ora('building for production...')
 spinner.start()
 
 rm(path.join(config.build.assetsRoot, config.build.assetsSubDirectory), err => {

template/build/check-versions.js

@@ -1,12 +1,13 @@
-var chalk = require('chalk')
-var semver = require('semver')
-var packageConfig = require('../package.json')
-var shell = require('shelljs')
+'use strict'
+const chalk = require('chalk')
+const semver = require('semver')
+const packageConfig = require('../package.json')
+const shell = require('shelljs')
 function exec (cmd) {
   return require('child_process').execSync(cmd).toString().trim()
 }
 
-var versionRequirements = [
+const versionRequirements = [
   {
     name: 'node',
     currentVersion: semver.clean(process.version),
@@ -23,9 +24,9 @@ if (shell.which('npm')) {
 }
 
 module.exports = function () {
-  var warnings = []
-  for (var i = 0; i < versionRequirements.length; i++) {
-    var mod = versionRequirements[i]
+  const warnings = []
+  for (let i = 0; i < versionRequirements.length; i++) {
+    const mod = versionRequirements[i]
     if (!semver.satisfies(mod.currentVersion, mod.versionRequirement)) {
       warnings.push(mod.name + ': ' +
         chalk.red(mod.currentVersion) + ' should be ' +
@@ -38,8 +39,8 @@ module.exports = function () {
     console.log('')
     console.log(chalk.yellow('To use this template, you must update following to modules:'))
     console.log()
-    for (var i = 0; i < warnings.length; i++) {
-      var warning = warnings[i]
+    for (let i = 0; i < warnings.length; i++) {
+      const warning = warnings[i]
       console.log('  ' + warning)
     }
     console.log()

template/build/dev-client.js

@@ -1,6 +1,7 @@
 /* eslint-disable */
+'use strict'
 require('eventsource-polyfill')
-var hotClient = require('webpack-hot-middleware/client?noInfo=true&reload=true')
+const hotClient = require('webpack-hot-middleware/client?noInfo=true&reload=true')
 
 hotClient.subscribe(function (event) {
   if (event.action === 'reload') {

template/build/dev-server.js

@@ -1,36 +1,37 @@
+'use strict'
 require('./check-versions')()
 
-var config = require('../config')
+const config = require('../config')
 if (!process.env.NODE_ENV) {
   process.env.NODE_ENV = JSON.parse(config.dev.env.NODE_ENV)
 }
 
-var opn = require('opn')
-var path = require('path')
-var express = require('express')
-var webpack = require('webpack')
-var proxyMiddleware = require('http-proxy-middleware')
-var webpackConfig = {{#if_or unit e2e}}(process.env.NODE_ENV === 'testing' || process.env.NODE_ENV === 'production')
+const opn = require('opn')
+const path = require('path')
+const express = require('express')
+const webpack = require('webpack')
+const proxyMiddleware = require('http-proxy-middleware')
+const webpackConfig = {{#if_or unit e2e}}(process.env.NODE_ENV === 'testing' || process.env.NODE_ENV === 'production')
   ? require('./webpack.prod.conf')
   : {{/if_or}}require('./webpack.dev.conf')
 
 // default port where dev server listens for incoming traffic
-var port = process.env.PORT || config.dev.port
+const port = process.env.PORT || config.dev.port
 // automatically open browser, if not set will be false
-var autoOpenBrowser = !!config.dev.autoOpenBrowser
+const autoOpenBrowser = !!config.dev.autoOpenBrowser
 // Define HTTP proxies to your custom API backend
 // https://github.com/chimurai/http-proxy-middleware
-var proxyTable = config.dev.proxyTable
+const proxyTable = config.dev.proxyTable
 
-var app = express()
-var compiler = webpack(webpackConfig)
+const app = express()
+const compiler = webpack(webpackConfig)
 
-var devMiddleware = require('webpack-dev-middleware')(compiler, {
+const devMiddleware = require('webpack-dev-middleware')(compiler, {
   publicPath: webpackConfig.output.publicPath,
   quiet: true
 })
 
-var hotMiddleware = require('webpack-hot-middleware')(compiler, {
+const hotMiddleware = require('webpack-hot-middleware')(compiler, {
   log: false,
   heartbeat: 2000
 })
@@ -46,7 +47,7 @@ var hotMiddleware = require('webpack-hot-middleware')(compiler, {
 
 // proxy api requests
 Object.keys(proxyTable).forEach(function (context) {
-  var options = proxyTable[context]
+  const options = proxyTable[context]
   if (typeof options === 'string') {
     options = { target: options }
   }
@@ -64,13 +65,13 @@ app.use(devMiddleware)
 app.use(hotMiddleware)
 
 // serve pure static assets
-var staticPath = path.posix.join(config.dev.assetsPublicPath, config.dev.assetsSubDirectory)
+const staticPath = path.posix.join(config.dev.assetsPublicPath, config.dev.assetsSubDirectory)
 app.use(staticPath, express.static('./static'))
 
-var uri = 'http://localhost:' + port
+const uri = 'http://localhost:' + port
 
-var _resolve
-var readyPromise = new Promise(resolve => {
+let _resolve
+const readyPromise = new Promise(resolve => {
   _resolve = resolve
 })
 
@@ -84,7 +85,7 @@ devMiddleware.waitUntilValid(() => {
   _resolve()
 })
 
-var server = app.listen(port)
+const server = app.listen(port)
 
 module.exports = {
   ready: readyPromise,

template/build/utils.js

@@ -1,9 +1,10 @@
-var path = require('path')
-var config = require('../config')
-var ExtractTextPlugin = require('extract-text-webpack-plugin')
+'use strict'
+const path = require('path')
+const config = require('../config')
+const ExtractTextPlugin = require('extract-text-webpack-plugin')
 
 exports.assetsPath = function (_path) {
-  var assetsSubDirectory = process.env.NODE_ENV === 'production'
+  const assetsSubDirectory = process.env.NODE_ENV === 'production'
     ? config.build.assetsSubDirectory
     : config.dev.assetsSubDirectory
   return path.posix.join(assetsSubDirectory, _path)
@@ -12,7 +13,7 @@ exports.assetsPath = function (_path) {
 exports.cssLoaders = function (options) {
   options = options || {}
 
-  var cssLoader = {
+  const cssLoader = {
     loader: 'css-loader',
     options: {
       minimize: process.env.NODE_ENV === 'production',
@@ -22,7 +23,7 @@ exports.cssLoaders = function (options) {
 
   // generate loader string to be used with extract text plugin
   function generateLoaders (loader, loaderOptions) {
-    var loaders = [cssLoader]
+    const loaders = [cssLoader]
     if (loader) {
       loaders.push({
         loader: loader + '-loader',
@@ -58,10 +59,10 @@ exports.cssLoaders = function (options) {
 
 // Generate loaders for standalone style files (outside of .vue)
 exports.styleLoaders = function (options) {
-  var output = []
-  var loaders = exports.cssLoaders(options)
-  for (var extension in loaders) {
-    var loader = loaders[extension]
+  const output = []
+  const loaders = exports.cssLoaders(options)
+  for (const extension in loaders) {
+    const loader = loaders[extension]
     output.push({
       test: new RegExp('\\.' + extension + '$'),
       use: loader

template/build/vue-loader.conf.js

@@ -1,6 +1,7 @@
-var utils = require('./utils')
-var config = require('../config')
-var isProduction = process.env.NODE_ENV === 'production'
+'use strict'
+const utils = require('./utils')
+const config = require('../config')
+const isProduction = process.env.NODE_ENV === 'production'
 
 module.exports = {
   loaders: utils.cssLoaders({

template/build/webpack.base.conf.js

@@ -1,7 +1,8 @@
-var path = require('path')
-var utils = require('./utils')
-var config = require('../config')
-var vueLoaderConfig = require('./vue-loader.conf')
+'use strict'
+const path = require('path')
+const utils = require('./utils')
+const config = require('../config')
+const vueLoaderConfig = require('./vue-loader.conf')
 
 function resolve (dir) {
   return path.join(__dirname, '..', dir)

template/build/webpack.dev.conf.js

@@ -1,10 +1,11 @@
-var utils = require('./utils')
-var webpack = require('webpack')
-var config = require('../config')
-var merge = require('webpack-merge')
-var baseWebpackConfig = require('./webpack.base.conf')
-var HtmlWebpackPlugin = require('html-webpack-plugin')
-var FriendlyErrorsPlugin = require('friendly-errors-webpack-plugin')
+'use strict'
+const utils = require('./utils')
+const webpack = require('webpack')
+const config = require('../config')
+const merge = require('webpack-merge')
+const baseWebpackConfig = require('./webpack.base.conf')
+const HtmlWebpackPlugin = require('html-webpack-plugin')
+const FriendlyErrorsPlugin = require('friendly-errors-webpack-plugin')
 
 // add hot-reload related code to entry chunks
 Object.keys(baseWebpackConfig.entry).forEach(function (name) {