Functional Fun - Monad Madness created by oliverjam - https://repl.it/Jvn3/0

Functional Fun - Monad Madness.js

// inc :: Number -> (Number,String)
const inc = x => y => [y + x, `${inc.name}${x} was called.`];
const inc1 = inc(1);

// dec :: Number -> (Number,String)
const dec = x => y => [y - x, `${dec.name}${x} was called.`];
const dec1 = dec(1);

// unit :: Number -> (Number,String)
const unit = x => [x, ''];

// Calls provided fn on num in tuple, returns tuple of result and both strings combined
// e.g. `bind([3, 'yoyoyo'], inc1)` -> [ 4, 'yoyoyo inc1 was called.' ]
// bind :: (Number,String) -> (Number -> (Number,String)) -> (Number,String)
const bind = (tuple, fn) => [fn(tuple[0])[0], tuple[1] + ' ' + fn(tuple[0])[1]];

// pipe :: [a] -> [a -> [b]] -> [b]
const pipe = (x, ...functions) => functions.reduce((acc, fn) => bind(acc, fn), x);


const double = x => [x * 2, `${double.name} was called.`];

bind([3, 'yoyoyo'], inc1);
// pipe(unit(7), inc1, double, dec1);