Intermediate Exercism • typescript

Strain

Challenge Overview

Implement the `keep` and `discard` operation on collections.

💡 View Solution

export function keep<T>(array: T[], predicate: (item: T) => boolean): T[] {
  const result: T[] = [];
  for (const item of array) {
    if (predicate(item)) {
      result.push(item);
    }
  }
  return result;
}

export function discard<T>(array: T[], predicate: (item: T) => boolean): T[] {
  return keep(array, (item: T) => !predicate(item));
}