feat(bun-plugin): include NODE_ENV as an allowed public environment variable

.changeset/few-lights-ask.md

@@ -0,0 +1,5 @@
+---
+"@arkenv/bun-plugin": minor
+---
+
+Include the `NODE_ENV` environment variable as one of the publicly exposed environment variables so it's possible to type it. Bun already exposes `process.env.NODE_ENV` to the frontend and now it's possible to get it correctly typed.

packages/bun-plugin/README.md

@@ -16,7 +16,7 @@
 - Build-time validation - app won't start if environment variables are invalid
 - Typesafe environment variables backed by TypeScript
 - Access to ArkType's powerful type system
-- Automatic filtering of client-exposed variables (defaults to `BUN_PUBLIC_*`)
+- Automatic filtering of client-exposed variables (defaults to `BUN_PUBLIC_*` and `NODE_ENV`)
 
 > [!IMPORTANT]
 > This plugin requires `arktype` to be installed in your project.
@@ -73,6 +73,7 @@ import { type } from 'arkenv';
 export default type({
   BUN_PUBLIC_API_URL: 'string',
   BUN_PUBLIC_DEBUG: 'boolean',
+  NODE_ENV: '"development" | "test" | "production" = "development"',
 });
 ```
 
@@ -112,6 +113,7 @@ await Bun.build({
     arkenv(type({
       BUN_PUBLIC_API_URL: 'string',
       BUN_PUBLIC_DEBUG: 'boolean',
+      NODE_ENV: '"development" | "test" | "production" = "development"',
     })),
   ],
 });

packages/bun-plugin/src/utils.test.ts

@@ -33,4 +33,16 @@ describe("Bun Plugin Utils", () => {
 		expect(envMap.has("PORT")).toBe(false);
 		expect(envMap.has("DATABASE_URL")).toBe(false);
 	});
+
+	it("should not filter out NODE_ENV", () => {
+		process.env.NODE_ENV = "development";
+
+		const envMap = processEnvSchema({
+			NODE_ENV: "'development' | 'test' | 'production'",
+		} as const);
+
+		// Check that NODE_ENV is present
+		expect(envMap.has("NODE_ENV")).toBe(true);
+		expect(envMap.get("NODE_ENV")).toBe(JSON.stringify("development"));
+	});
 });

packages/bun-plugin/src/utils.ts

@@ -17,8 +17,11 @@ export function processEnvSchema<T extends SchemaShape>(
 		env: config?.env ?? process.env,
 	});
 	const prefix = "BUN_PUBLIC_";
+	const allowed = new Set(["NODE_ENV"]);
 	const filteredEnv = Object.fromEntries(
-		Object.entries(env).filter(([key]) => key.startsWith(prefix)),
+		Object.entries(env).filter(
+			([key]) => allowed.has(key) || key.startsWith(prefix),
+		),
 	);
 	const envMap = new Map<string, string>();
 	for (const [key, value] of Object.entries(filteredEnv)) {