Takes a predicate and array, like Array.filter(), but only keeps x if pred(x) === false.
const reject = (pred, array) => array.filter((...args) => !pred(...args));reject(x => x % 2 === 0, [1, 2, 3, 4, 5]); // [1, 3, 5]
reject(word => word.length > 4, ['Apple', 'Pear', 'Kiwi', 'Banana']); // ['Pear', 'Kiwi']