30-seconds-of-code/snippets/js/s/compose-functions.md

title, type, language, tags, cover, dateModified

title	type	language	tags	cover	dateModified
Compose functions	snippet	javascript	function	digital-nomad-16	2020-10-22T20:23:47+03:00

Performs right-to-left function composition.

• Use Array.prototype.reduce() to perform right-to-left function composition.
• The last (rightmost) function can accept one or more arguments; the remaining functions must be unary.

const compose = (...fns) =>
  fns.reduce((f, g) => (...args) => f(g(...args)));

const add5 = x => x + 5;
const multiply = (x, y) => x * y;
const multiplyAndAdd5 = compose(
  add5,
  multiply
);
multiplyAndAdd5(5, 2); // 15