It is an approach where result of one function passed on to next function.
const add = (x, y) => x+y;
const subtract = (x) => x-4;
const multiply = (x) => x * 8;
// result of `add` is passed to `subtract` and its result passed to `multiply`.
const result = multiply(subtract(add(2, 3)));
result;
> 8
That looks readable but what if we have more functions to call one after other.
Let's try little cleaner approach.
const compose = (...functions) => x => functions.reduceRight((total, f) => f(total), x);
const add = x => x+2;
const subtract = x => x-1;
const multiply = x => x * 8;
compose(multiply, subtract, add)(2);
> 24
We can also use reduce to implement:
const pipe = (...functions) => x => functions.reduce((total, f) => f(total), x);
const add = x => x+2;
const subtract = x => x-1;
const multiply = x => x * 8;
pipe(add, subtract, multiply)(2);
> 24
pipe - performs from left-to-right.
compose - performs from right-to-left.
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