feat: add dangerouslyRunInProduction flag to worker and server options

src/browser/setupWorker/setupWorker.ts

@@ -21,6 +21,7 @@ import { mergeRight } from '~/core/utils/internal/mergeRight'
 import { LifeCycleEventsMap } from '~/core/sharedOptions'
 import { SetupWorker } from './glossary'
 import { supportsReadableStreamTransfer } from '../utils/supportsReadableStreamTransfer'
+import { isProduction } from '~/core/utils/internal/isProduction'
 
 interface Listener {
   target: EventTarget
@@ -177,6 +178,14 @@ export class SetupWorkerApi
       options,
     ) as SetupWorkerInternalContext['startOptions']
 
+    invariant(
+      !this.context.startOptions.dangerouslyRunInProduction && isProduction(),
+      devUtils.formatMessage(
+        'Failed to call "setupWorker" in a production environment. Please make sure you enable API mocking conditionally so it doesn\'t leak to production.',
+      ),
+      'https://github.com/mswjs/msw/issues/1703',
+    )
+
     return await this.startHandler(this.context.startOptions, options)
   }
 

src/browser/setupWorker/start/utils/prepareStartHandler.ts

@@ -15,6 +15,7 @@ export const DEFAULT_START_OPTIONS: RequiredDeep<StartOptions> = {
   quiet: false,
   waitUntilReady: true,
   onUnhandledRequest: 'warn',
+  dangerouslyRunInProduction: false,
   findWorker(scriptURL, mockServiceWorkerUrl) {
     return scriptURL === mockServiceWorkerUrl
   },

src/core/sharedOptions.ts

@@ -11,6 +11,10 @@ export interface SharedOptions {
    * @example server.listen({ onUnhandledRequest: 'error' })
    */
   onUnhandledRequest?: UnhandledRequestStrategy
+  /**
+   * A flag to enable MSW in production (NODE_ENV === 'production'), otherwise it will throw an error
+   */
+  dangerouslyRunInProduction?: boolean
 }
 
 export type LifeCycleEventsMap = {

src/core/utils/internal/isProduction.ts

@@ -0,0 +1,3 @@
+export function isProduction(): boolean {
+  return process && process.env.NODE_ENV === 'production'
+}

src/node/SetupServerApi.ts

@@ -14,9 +14,11 @@ import { handleRequest } from '~/core/utils/handleRequest'
 import { devUtils } from '~/core/utils/internal/devUtils'
 import { SetupServer, SetupServerInternalContext } from './glossary'
 import { isNodeExceptionLike } from './utils/isNodeExceptionLike'
+import { isProduction } from '~/core/utils/internal/isProduction'
 
 const DEFAULT_LISTEN_OPTIONS: RequiredDeep<SharedOptions> = {
   onUnhandledRequest: 'warn',
+  dangerouslyRunInProduction: false,
 }
 
 export class SetupServerApi
@@ -101,6 +103,13 @@ export class SetupServerApi
       options,
     ) as RequiredDeep<SharedOptions>
 
+    invariant(
+      !this.resolvedOptions.dangerouslyRunInProduction && isProduction(),
+      devUtils.formatMessage(
+        'Failed to call "setupWorker" in a production environment. Please make sure you enable API mocking conditionally so it doesn\'t leak to production.',
+      ),
+      'https://github.com/mswjs/msw/issues/1703',
+    )
     // Apply the interceptor when starting the server.
     this.interceptor.apply()