In some cases, you might want to define your own logic to determine whether to return an ok value or err value. You can do this by using and API.
import {ok, err, type Result} from 'unwrapit'
export function addNumber(a: number, b: number): Result<number, string> {
if (a < b) {
return err('a should greater than b')
}
if (a === b) {
return err("a shouldn't equal to b")
}
return ok(a + b)
}