Add a Config.nonEmptyString constructor

[titouancreach]

What is the problem this feature would solve?

Most of the time, empty string is not a valid configuration, it often comes from a .env file not filled in by the user (file that comes from .env.example or something)

# Redirect the emails to this user
EMAIL_REDIRECT=

DB_URL=

Some other packages (like https://env.t3.gg/docs/core) have an option to treat empty string as undefined.

I believe this case is common enough to be a part of the Effect repo.

What is the feature you are proposing to solve the problem?

Add a new constructor:

const dbUrl = yield* Config. stringNonEmpty("DB_URL");

What alternatives have you considered?

Making my own function like the one @tim-smart did:

import { Config, ConfigError, Either, Redacted } from "effect"

export const nonEmptyString = (name: string) =>
  Config.string(name).pipe(
    Config.mapOrFail(_ => {
      const trimmed = _.trim()
      return trimmed !== ""
        ? Either.right(trimmed)
        : Either.left(ConfigError.MissingData([], "must not be empty"))
    }),
  )