fix types

Author: Haroenv

global.d.ts

@@ -1 +1,8 @@
 declare const __DEV__: boolean;
+
+declare namespace NodeJS {
+  // override the type set by Next (in examples), which sets NODE_ENV to readonly globally
+  interface ProcessEnv {
+    NODE_ENV: 'development' | 'production' | 'test';
+  }
+}