Make bugs impossible.
One TypeScript tip at a time.

process.env.LOG_LEVEL
process.env.LOG_FILE
// ⛔️       ^ string | undefined
// ⛔️ No autocomplete

import { z } from "zod"

const EnvSchema = z.object({
  LOG_LEVEL: z
    .union([z.literal("debug"), z.literal("info")])
    .default("info"),
  LOG_FILE: z.string(),
})

declare global {
  namespace NodeJS {
    interface ProcessEnv extends z.infer<typeof EnvSchema> {}
  }
}

process.env = { ...process.env, ...EnvSchema.parse(process.env) }
// ✅ Throws if LOG_FILE is missing
// ✅ Defaults LOG_LEVEL to "info" if missing

process.env.LOG_LEVEL
// ✅       ^ "debug" | "info"
// ✅ Autocomplete

process.env.LOG_FILE
// ✅       ^ string
// ✅ Autocomplete