Ensure NODE_ENV is replaced correctly with swc

packages/next/build/swc/options.js

@@ -44,6 +44,10 @@ function getBaseSWCOptions({
             typeofs: {
               window: globalWindow ? 'object' : 'undefined',
             },
+            envs: {
+              NODE_ENV: development ? '"development"' : '"production"',
+            },
+            // TODO: handle process.browser to match babel replacing as well
           },
         },
         regenerator: {

test/integration/non-standard-node-env-warning/test/index.test.js

@@ -1,12 +1,14 @@
 /* eslint-env jest */
-
+import glob from 'glob'
+import fs from 'fs-extra'
 import { join } from 'path'
 import {
   findPort,
   launchApp,
   killApp,
   waitFor,
   initNextServerScript,
+  nextBuild,
 } from 'next-test-utils'
 
 const appDir = join(__dirname, '..')
@@ -77,6 +79,29 @@ describe('Non-Standard NODE_ENV', () => {
     expect(output).not.toContain(warningText)
   })
 
+  it('should still DCE NODE_ENV specific code', async () => {
+    await nextBuild(appDir, undefined, {
+      env: {
+        NODE_ENV: 'test',
+      },
+    })
+
+    const staticFiles = glob.sync('**/*.js', {
+      cwd: join(appDir, '.next/static'),
+    })
+    expect(staticFiles.length).toBeGreaterThan(0)
+
+    for (const file of staticFiles) {
+      const content = await fs.readFile(
+        join(appDir, '.next/static', file),
+        'utf8'
+      )
+      if (content.match(/cannot find module/i)) {
+        throw new Error(`${file} contains module not found error`)
+      }
+    }
+  })
+
   it('should show the warning with NODE_ENV set to invalid value', async () => {
     let output = ''
 

test/lib/next-test-utils.js

@@ -129,10 +129,10 @@ export function runNextCommand(argv, options = {}) {
   // Let Next.js decide the environment
   const env = {
     ...process.env,
-    ...options.env,
     NODE_ENV: '',
     __NEXT_TEST_MODE: 'true',
     NEXT_PRIVATE_OUTPUT_TRACE_ROOT: path.join(__dirname, '../../'),
+    ...options.env,
   }
 
   return new Promise((resolve, reject) => {