update

build/build.js

@@ -1,8 +1,6 @@
 'use strict'
 require('./check-versions')()
 
-process.env.NODE_ENV = 'production'
-
 const ora = require('ora')
 const rm = require('rimraf')
 const path = require('path')
@@ -10,8 +8,12 @@ const chalk = require('chalk')
 const webpack = require('webpack')
 const config = require('../config')
 const webpackConfig = require('./webpack.prod.conf')
+var connect = require('connect')
+var serveStatic = require('serve-static')
 
-const spinner = ora('building for production...')
+const spinner = ora(
+  'building for ' + process.env.env_config + ' environment...'
+)
 spinner.start()
 
 rm(path.join(config.build.assetsRoot, config.build.assetsSubDirectory), err => {
@@ -30,16 +32,36 @@ rm(path.join(config.build.assetsRoot, config.build.assetsSubDirectory), err => {
     )
 
     if (stats.hasErrors()) {
-      console.log(chalk.red('  Build failed with errors.\n'))
+      console.log(chalk.red(' Build failed with errors.\n'))
       process.exit(1)
     }
 
-    console.log(chalk.cyan('  Build complete.\n'))
+    console.log(chalk.cyan(' Build complete.\n'))
     console.log(
       chalk.yellow(
-        '  Tip: built files are meant to be served over an HTTP server.\n' +
-          "  Opening index.html over file:// won't work.\n"
+        ' Tip: built files are meant to be served over an HTTP server.\n' +
+        " Opening index.html over file:// won't work.\n"
       )
     )
+
+    if (process.env.npm_config_preview) {
+      const port = 9526
+      const host = 'http://localhost:' + port
+      const basePath = config.build.assetsPublicPath
+      const app = connect()
+
+      app.use(
+        basePath,
+        serveStatic('./dist', {
+          index: ['index.html', '/']
+        })
+      )
+
+      app.listen(port, function() {
+        console.log(
+          chalk.green(`> Listening at  http://localhost:${port}${basePath}`)
+        )
+      })
+    }
   })
 })

build/check-versions.js

@@ -36,10 +36,10 @@ module.exports = function() {
     if (!semver.satisfies(mod.currentVersion, mod.versionRequirement)) {
       warnings.push(
         mod.name +
-          ': ' +
-          chalk.red(mod.currentVersion) +
-          ' should be ' +
-          chalk.green(mod.versionRequirement)
+        ': ' +
+        chalk.red(mod.currentVersion) +
+        ' should be ' +
+        chalk.green(mod.versionRequirement)
       )
     }
   }