30-seconds-of-code/snippets/complement.md

title, tags, cover, firstSeen, lastUpdated

title	tags	cover	firstSeen	lastUpdated
Logical complement	function,logic	blog_images/flower-portrait-10.jpg	2020-05-13T11:28:33+03:00	2020-09-15T16:28:04+03:00

Returns a function that is the logical complement of the given function, fn.

• Use the logical not (!) operator on the result of calling fn with any supplied args.

const complement = fn => (...args) => !fn(...args);

const isEven = num => num % 2 === 0;
const isOdd = complement(isEven);
isOdd(2); // false
isOdd(3); // true