30-seconds-of-code/snippets/none.md

title, tags, expertise, cover, firstSeen, lastUpdated

title	tags	expertise	cover	firstSeen	lastUpdated
Test if all array elements are falsy	array	beginner	blog_images/bug.jpg	2018-02-14T11:46:15+02:00	2020-10-21T21:54:53+03:00

Checks if the provided predicate function returns false for all elements in a collection.

• Use Array.prototype.some() to test if any elements in the collection return true based on fn.
• Omit the second argument, fn, to use Boolean as a default.

const none = (arr, fn = Boolean) => !arr.some(fn);

none([0, 1, 3, 0], x => x == 2); // true
none([0, 0, 0]); // true