Turbopack Compat, Better Types, and Quality Improvements

Three fixes that make CtroEnv work seamlessly with modern tooling and feel more polished.

Turbopack Compatible Build Validation

The withCtroEnv() Next.js wrapper previously ran validation inside a webpack config hook. With Next.js 16 defaulting to Turbopack, that validation was silently skipped.

Validation now runs eagerly at config load time — before any bundler touches your code:

// next.config.ts — works with webpack, Turbopack, or any future bundler
export default withCtroEnv(schema, nextConfig)

Errors are caught immediately when the config is loaded, not buried inside a build step. The behavior is identical — failed validation still exits with code 1 — but it now works regardless of which bundler Next.js uses.

pick() Without as const

pick() now uses a const type parameter, eliminating the need for as const on every call:

// Before — required as const for literal types
const env = defineEnv({
  NODE_ENV: pick(["dev", "prod", "test"] as const),
})
 
// After — as const is automatic
const env = defineEnv({
  NODE_ENV: pick(["dev", "prod", "test"]),
})

The inferred type is "dev" | "prod" | "test" in both cases. One less thing to remember.

env.meta.get() Returns string | undefined

env.meta.get("KEY") now returns string | undefined instead of unknown:

const raw = env.meta.get("JWT_SECRET")
//    ^? string | undefined — no cast needed

Since env values are always strings at runtime, the return type now reflects reality. The undefined case handles missing keys, matching standard JavaScript access patterns.

Full Changelog

See the GitHub Release for the complete list of changes.