Keep all your process.env in a config file, so it is easy to check env vars available

env.ts

import { cleanEnv, str, num, url } from 'envalid'

const env = cleanEnv(process.env, {
  GRAPHQL_URL: url({
    devDefault: 'http://localhost:4000/graphql',
  }),
  PORT: num({
    devDefault: 3000,
  }),
  A: str(),
})

export default env;