feat: add --modern to nuxt start (#4254)

packages/babel-preset-app/src/index.js

@@ -39,7 +39,7 @@ module.exports = (context, options = {}) => {
   const {
     buildTarget,
     loose = false,
-    useBuiltIns = 'usage',
+    useBuiltIns = (modern ? false : 'usage'),
     modules = false,
     polyfills: userPolyfills,
     ignoreBrowserslistConfig = modern,

packages/cli/src/commands/start.js

@@ -9,7 +9,18 @@ export default {
   usage: 'start <dir>',
   options: {
     ...common,
-    ...server
+    ...server,
+    modern: {
+      alias: 'm',
+      type: 'boolean',
+      description: 'Build app for modern browsers',
+      prepare(cmd, options, argv) {
+        options.build = options.build || {}
+        if (argv.modern) {
+          options.build.modern = !!argv.modern
+        }
+      }
+    }
   },
   async run(cmd) {
     const argv = cmd.getArgv()