pub fn bundle(
  mod: String,
  func: String,
  resolve_id: fn(String, String) -> String,
  load: fn(String) -> String,
) -> promise.Promise(Result(String, String))

pub fn do_bundle(
  input: String,
  resolve_id: fn(String, String) -> String,
  load: fn(String) -> String,
) -> promise.Promise(Result(String, String))