Cannot able create a Record from another Record (With all optional keys)

I have 250 fields in my prop type.

For now, I did this

let mapper: (a) => b = (a) => {
  ({ t ?: a.t
  , l ?: a.l->intToString
  , p ?: a.p->arrayToString
  } : b)
}

But in this also, If you remove any key for code … rescript will compile successfully. There is no way to ensure all keys are copied. That needs to be manage by team.