env.d.ts

Getting tired of looking up how to strongly type environment variables you know will exist just so you can get rid of string | undefined? Tired of visiting https://www.totaltypescript.com/how-to-strongly-type-process-env for the thousandth time?

Run this handy little tool to quickly generate a declaration file for your env vars!

npx env.d.ts

When your .env file looks like this

HELLO=world

You'll get this env.d.ts file

/**
 * This file was autogenerated with "npx env.d.ts"
 * Manual edits are okay, but will be overwritten when you run this command.
 * Be sure to _include_ this file in your tsconfig.json
 */
namespace NodeJS {
  interface ProcessEnv {
    HELLO: string
  }
}

The tool will look for .env and .env.local by default, but you can give it other files

npx env.d.ts .env.development

env.d.ts gets generated in your current working directory, however you can specify an out directory

npx env.d.ts --out-dir src
# or
npx env.d.ts -o src

Disclaimer

This tool doesn't do much and isn't intended to become a replacement for other dotenv tools. It is simply a means to an end when working in a new project. You may want to omit certain environment variables you have in your dotenv files that you know you won't be explicitly using in code, like AWS_PROFILE, or you may want to decorate keys with descriptions of when/how to use them. Use this tool to generate it the first time and clean it up or maintain how you see fit.