feat(cli-service): add stdin flag to build (#5376)

packages/@vue/cli-service/lib/commands/build/index.js

@@ -37,7 +37,8 @@ module.exports = (api, options) => {
       '--report': `generate report.html to help analyze bundle content`,
       '--report-json': 'generate report.json to help analyze bundle content',
       '--skip-plugins': `comma-separated list of plugin names to skip for this run`,
-      '--watch': `watch for changes`
+      '--watch': `watch for changes`,
+      '--stdin': `close when stdin ends`
     }
   }, async (args, rawArgs) => {
     for (const key in defaults) {
@@ -155,6 +156,13 @@ async function build (args, api, options) {
     })
   }
 
+  if (args.stdin) {
+    process.stdin.on('end', () => {
+      process.exit(0)
+    })
+    process.stdin.resume()
+  }
+
   // Expose advanced stats
   if (args.dashboard) {
     const DashboardPlugin = require('../../webpack/DashboardPlugin')