Types · hard

48. Contract-Binding Types

Defining types that enforce a runtime structure (Schema validation logic).

Define a `Validator<T>` as a function `(val: unknown) => T` that throws if invalid.

Required in your answer: Validator<T>(val: unknown) => T

Transpiled, then run in a sandbox

type Validator<T> = (val: unknown) => T;
const stringVal: Validator<string> = (v) => {
  if (typeof v !== 'string') throw 'err';
  return v;
};

Output appears here.