MonadPrimus

MonadPrimus is a library of functional programming.
MonadPrimus includes lazy evaluation list, tuple, function wrapper which can curry and compose, Maybe and Either monad and so on.

How to use

node.js

Install MonadPrimus.js:

npm install monadprimus

Use module:

var M = require('monadprimus');

Browser

<script src="monadprimus.js"></script>

Examples

Lazy Evaluation List

// outputs [1, 4, 9, 16, 25]
console.log(M.L(1, 2, 3).concat(M.L(4, 5)).map(x => x * x).take());
// outputs [1, 3, 2, 6]
console.log(M.L(1, 2).bind(x => M.L(x * 2, x * 3).take());
// outputs [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
console.log(M.L.N(2).filter(
  x => x < 4 || M.L.range(2, Math.floor(Math.sqrt(x))).every(y => x % y !== 0)).take(10));

Tuple

// outputs 1
console.log(M.T(1, 2, 3)(0));
// outputs [1, 2, 3]
console.log(M.T(1, 2, 3).toArray());
// outputs "(1,2,3)"
console.log(M.T(1, 2, 3).toString());

Function Wrapper

// curring: outputs 9
console.log(M.F((x, y, z) => x + y + z)(3)(2)(4));
// pipe: outputs 10
console.log(M.F((x, y) => x * y).pipe(x => x / 3).pipe(x => x * 2)(3)(5));
// placeholder: outputs "765"
console.log(M.F((x, y, z) => x + y + z)(M.$3, M.$2, M.$1)("5")("6")("7"));

Maybe monad

// outputs "Just 6"
console.log(M.Just(3).bind(x => M.Just(x + 3)).toString());
// outputs "Nothing"
console.log(M.Nothing.bind(x => M.Just(x + 3)).toString());
// outputs "Nothing"
console.log(M.Just(3).bind(x => M.Nothing).toString());