Validate an unknown response

Validate unknown response objects before treating them as typed data.

Original Pearto instructional example. Test it in your own environment and adapt it to your requirements.

type Person = {name:string; age:number};
function isPerson(value:unknown):value is Person {
  return typeof value === 'object' && value !== null &&
    'name' in value && typeof value.name === 'string' &&
    'age' in value && typeof value.age === 'number';
}
const payload:unknown = {name:'Ada', age:34};
if (isPerson(payload)) console.log(payload.name);