Generated client has type error when using optional AuthParams

[tuckers-tech]

I have a system that authenticates via secure cookie or api token (depending on if the client is the browser or CLI). I currently have this set up on the encore side with:

interface AuthParams {
  cookie?: Header<'Cookie'>
  token?: Header<'x-api-token'>
}

This works great on the backend side, I didn't run into any issues until I started integrating the client. I can generate the client but when I try and build (exec TS check) I'm running into an issue with the following generated lines in the callAPI method

if (authData) {
  init.headers['cookie'] = authData.cookie
  init.headers['x-api-token'] = authData.token
}

This throws the following error because both authData.cookie and authData.token are optional

Type 'string | undefined' is not assignable to type 'string'.
  Type 'undefined' is not assignable to type 'string'.