Multiuser support (#60)

lib/env.server.ts

@@ -0,0 +1,31 @@
+import { z } from "zod"
+
+const zodEnv = z.object({
+  AUTH_SECRET: z.string(),
+  NEXT_PUBLIC_DEMO: z.string().optional(),
+})
+
+declare global {
+  interface ProcessEnv extends z.TypeOf<typeof zodEnv> {
+    AUTH_SECRET: string;
+    NEXT_PUBLIC_DEMO?: string;
+  }
+}
+
+try {
+  zodEnv.parse(process.env)
+} catch (err) {
+  if (err instanceof z.ZodError) {
+    const { fieldErrors } = err.flatten()
+    const errorMessage = Object.entries(fieldErrors)
+      .map(([field, errors]) =>
+        errors ? `${field}: ${errors.join(", ")}` : field,
+      )
+      .join("\n ")
+    
+    console.error(
+      `Missing environment variables:\n ${errorMessage}`,
+    )
+    process.exit(1)
+  }
+}