*Question* Is it possible to apply "strict" mode to avoid coercing data types, but still allowing transforming?

I have an API that receives different fields, one of which would be a zipcode-like document. Normally, users can send documents with punctuation, like dashes and commas, and I’d like to:

1. Not allow any values that aren’t strings (example: Yup coerces [1,2] into 12 in non strict mode)
2. Remove non digits from the text (I used transform() to change 1.2.3 into 123, for example).

However, it seems strict mode only allows one or the other, never both. I can think of solutions involving the test() method, but just to make sure I’m not missing out on any features, is it feasible without using test()?

[jquense]

There isn’t a built in way, but you can build your own string schema that does it.

class StrictString extends string {
  constructor() {
    super()
    this.transforms = [] // remove the default coercion transforms
  }
}

[ProtoCh4os]

Great! It worked! Thanks for the help @jquense