Feature Idea: dependent variables

[janl]

First of all, thank you for providing such a useful utility <3

In my scenario: I want to validate an optional username and password, but also say that if there is one without the other, the validation should fail. E.g. allow configuration against a resources that allows authenticated and unauthenticated requests. One can opt to add user/pass, or not user/pass, but if the provide user/pass, BOTH have to be there.

This can be solved in a transform function, which is what I’m going with for now, but something like this would be nice:

let config = {
  username: str(dependsOn:['password']),
  password: str(dependsOn: ['username'])
}

This is just to sketch what this could look like. Using an array of depends could open this up to more than two dependent variables. Although having to make the dependency on both sides will explode maintenance complexity quickly.

Alternatively, maybe this can be done with grouping:

let config = {
  group: {
    username: str(dependsOn:['password']),
    password: str(dependsOn: ['username'])
  }
}

where group is an arbitrary label, but the semantics are: if one of the values is missing, validation fails.

Another variant would be explicit grouping:

let config = {
  username: str(),
  password: str()
}

const options = {
  groups: [['username', 'password']]
}
envalid.cleanEnv(process.env, config, options)

[SimenB]

Duplicate of #78, isn't it?

[janl]

totally 🤦‍♂️ I swear I looked through all open and closed issues for a discussion on this, but I must have missed it.

[SimenB]

I still love the idea, would love for you to weigh in on that one 🙂