Interface ComparatorWithPredicateFactory<T>

A factory that holds a list of comparators and attached predicates. Use the orIf method to push additional comparators with predicates, thus broadening the range of accepted values and types.

orElse and orElseThrow will produce the final Comparator, that will only accept values which match one of the added predicates. Predicates will be checked in the same order as they were added.

On each comparator call both arguments must match the same predicate. If no such predicate exists, the comparator will either throw an error or use a fallback comparator, depending on whether you used orElseThrow or orElse respectively.

Use type guards as predicates to ensure the best type safety.

Example

// inferred type: Comparator<string | number>
const unionComparator = comparatorWithPredicate(isString, ignoreCase)
  .orIf(isNumber, reversedOrder)
  .orElseThrow();

// set type explicitly when not using a proper type guard; otherwise any will be inferred
// inferred type: Comparator<string | number | boolean | Person>
const anotherUnionComparator = comparatorWithPredicate(isPerson, personComparator)
  .orIf<string | number | boolean>(isPrimitive, naturalOrder)
  .orElseThrow();

// not provided by this library
declare const isString = (value: any) => value is string;
declare const isNumber = (value: any) => value is number;
declare const isPerson = (value: any) => value is Person;
declare const isPrimitive = (value: any) => boolean;