refactor: CJS -> ESM (#7178)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: kyle-ssg

frontend/.babelrc

@@ -0,0 +1,90 @@
+// Shared Express routes used by both RspackDevServer (dev) and api/index.js (prod)
+require('dotenv').config()
+const bodyParser = require('body-parser')
+
+module.exports = function setupRoutes(app) {
+  app.get('/config/project-overrides', (req, res) => {
+    const getVariable = ({ name, value }) => {
+      if (!value || value === 'undefined') {
+        if (typeof value === 'boolean') {
+          return `    ${name}: false,\n                `
+        }
+        return ''
+      }
+      if (typeof value !== 'string') {
+        return `    ${name}: ${value},\n            `
+      }
+      return `    ${name}: '${value.trim()}',\n        `
+    }
+    const envToBool = (name, defaultVal) => {
+      const envVar = `${process.env[name]}`
+      if (envVar === 'undefined') {
+        return defaultVal
+      }
+      return envVar === 'true' || envVar === '1'
+    }
+    const sha = ''
+    const values = [
+      { name: 'preventSignup', value: envToBool('PREVENT_SIGNUP', false) },
+      { name: 'preventEmailPassword', value: envToBool('PREVENT_EMAIL_PASSWORD', false) },
+      { name: 'preventForgotPassword', value: envToBool('PREVENT_FORGOT_PASSWORD', false) },
+      { name: 'superUserCreateOnly', value: envToBool('ONLY_SUPERUSERS_CAN_CREATE_ORGANISATIONS', false) },
+      { name: 'flagsmith', value: process.env.FLAGSMITH_ON_FLAGSMITH_API_KEY },
+      { name: 'headway', value: process.env.HEADWAY_API_KEY },
+      { name: 'ga', value: process.env.GOOGLE_ANALYTICS_API_KEY },
+      { name: 'sha', value: sha },
+      { name: 'crispChat', value: process.env.CRISP_WEBSITE_ID },
+      { name: 'pylonAppId', value: process.env.PYLON_APP_ID },
+      { name: 'fpr', value: process.env.FIRST_PROMOTER_ID },
+      { name: 'sentry', value: process.env.SENTRY_API_KEY },
+      { name: 'api', value: process.env.FLAGSMITH_PROXY_API_URL ? '/api/v1/' : process.env.FLAGSMITH_API_URL },
+      { name: 'apiProxyEnabled', value: !!process.env.FLAGSMITH_PROXY_API_URL },
+      { name: 'maintenance', value: envToBool('ENABLE_MAINTENANCE_MODE', false) },
+      { name: 'flagsmithClientAPI', value: process.env.FLAGSMITH_ON_FLAGSMITH_API_URL },
+      { name: 'disableAnalytics', value: envToBool('DISABLE_ANALYTICS_FEATURES', false) },
+      { name: 'flagsmithAnalytics', value: envToBool('ENABLE_FLAG_EVALUATION_ANALYTICS', true) },
+      { name: 'flagsmithRealtime', value: envToBool('ENABLE_FLAGSMITH_REALTIME', false) },
+      { name: 'amplitude', value: process.env.AMPLITUDE_API_KEY },
+      { name: 'reo', value: process.env.REO_API_KEY },
+      { name: 'delighted', value: process.env.DELIGHTED_API_KEY },
+      { name: 'capterraKey', value: process.env.CAPTERRA_API_KEY },
+      { name: 'hideInviteLinks', value: envToBool('DISABLE_INVITE_LINKS', false) },
+      { name: 'linkedinPartnerTracking', value: envToBool('LINKEDIN_PARTNER_TRACKING', false) },
+      { name: 'albacross', value: process.env.ALBACROSS_CLIENT_ID },
+      { name: 'useSecureCookies', value: envToBool('USE_SECURE_COOKIES', true) },
+      { name: 'cookieSameSite', value: process.env.USE_SECURE_COOKIES },
+      { name: 'cookieAuthEnabled', value: process.env.COOKIE_AUTH_ENABLED },
+      { name: 'githubAppURL', value: process.env.GITHUB_APP_URL },
+      { name: 'e2eToken', value: process.env[`E2E_TEST_TOKEN_${(process.env.ENV || 'dev').toUpperCase()}`] || process.env.E2E_TEST_TOKEN || '' },
+      { name: 'evaluationAnalyticsServerUrl', value: process.env.EVALUATION_ANALYTICS_SERVER_URL },
+      { name: 'gramProjectSlug', value: process.env.GRAM_PROJECT_SLUG },
+      { name: 'gramMcpUrl', value: process.env.GRAM_MCP_URL },
+    ]
+    let output = values.map(getVariable).join('')
+    res.setHeader('Cache-Control', 's-max-age=1, stale-while-revalidate')
+    res.setHeader('content-type', 'application/javascript')
+    const e2eScript = process.env.E2E ? 'window.E2E=true;' : ''
+    res.send(`${e2eScript}window.projectOverrides = {\n        ${output}\n    };`)
+  })
+
+  // Optionally proxy the API
+  if (process.env.FLAGSMITH_PROXY_API_URL) {
+    const { createProxyMiddleware } = require('http-proxy-middleware')
+    app.use(
+      '/api/v1/',
+      createProxyMiddleware({
+        changeOrigin: true,
+        target: process.env.FLAGSMITH_PROXY_API_URL,
+        xfwd: true,
+      }),
+    )
+  }
+
+  app.use(bodyParser.json())
+
+  app.get('/health', (req, res) => {
+    // eslint-disable-next-line
+    console.log('Healthcheck complete')
+    res.send('OK')
+  })
+}

frontend/api/dev-routes.js

@@ -153,11 +153,8 @@ if (process.env.FLAGSMITH_PROXY_API_URL) {
 }
 
 if (isDev) {
-  // Serve files from src directory and use webpack-dev-server
-  // eslint-disable-next-line
-  console.log('Enabled Webpack Hot Reloading')
-  const webpackMiddleware = require('./middleware/webpack-middleware')
-  webpackMiddleware(app)
+  // In dev mode, use `npm run dev` which starts @rspack/dev-server
+  // This code path only runs if someone starts `node ./api` directly in dev
   app.set('views', 'web/')
   app.use(express.static('web'))
 } else {

frontend/api/index.js

@@ -1,6 +1,6 @@
 import Constants from 'common/constants'
 
-module.exports = (envId, { USER_ID }, userId) => {
+export default (envId, { USER_ID }, userId) => {
   const url = new URL('identities/', Constants.getFlagsmithSDKUrl())
   url.searchParams.append('identifier', userId || USER_ID)
 

frontend/api/middleware/webpack-middleware.js

@@ -1,4 +1,4 @@
-module.exports = (
+export default (
   envId,
   { FEATURE_NAME, FEATURE_NAME_ALT, USER_ID },
   userId,

frontend/common/code-help/create-user/create-user-curl.js

@@ -1,5 +1,5 @@
 import Constants from 'common/constants'
-module.exports = (
+export default (
   envId,
   { FEATURE_NAME, FEATURE_NAME_ALT, USER_ID },
   userId,

frontend/common/code-help/create-user/create-user-dotnet.js

@@ -1,4 +1,4 @@
-module.exports = (
+export default (
   envId,
   { FEATURE_NAME, FEATURE_NAME_ALT, USER_ID },
   userId,

frontend/common/code-help/create-user/create-user-flutter.js

@@ -1,6 +1,6 @@
 import Constants from 'common/constants'
 
-module.exports = (
+export default (
   envId,
   { FEATURE_NAME, FEATURE_NAME_ALT, USER_ID },
   userId,

frontend/common/code-help/create-user/create-user-go.js

@@ -1,6 +1,6 @@
 import Constants from 'common/constants'
 
-module.exports = (
+export default (
   envId,
   { FEATURE_NAME, FEATURE_NAME_ALT, LIB_NAME, LIB_NAME_JAVA, USER_ID },
   userId,