Functional Typescript Series

Function composition is the process of combining two or more functions to produce a new function. Composing functions together is like snapping together a series of pipes for our data to flow through.

const trim = (s: string) => s.trim();
const capitalize = (s: string) => s.toUpperCase();

	const compose = <T>(f: (x: T) => T, g: (x: T) => T) => (x: T) => f(g(x));
	const compose2 = <T1, T2, T3>(f: (x: T2) => T3, g: (x: T1) => T2) => (x: T1) => f(g(x));
	const composeMany = <T>(...functions: Array<(arg: T) => T>) =>
	(arg: any) =>
	functions.reduce((prev, curr) => {
	return curr(prev);
	}, arg);
	const func1 = <T>(x: T) => x;
	const func2 = <T>(x: T) => x;
	const func3 = <T>(x: T) => x;
	const func4 = <T>(x: T) => x;
	const func5 = <T>(x: T) => x;
	const composed1 = composeMany(func1, func2, func3, func4);
	const composed2 = composeMany(func1, func2, func3, func4, func5);

view raw composeMany.ts hosted with ❤ by GitHub