functional.js

functional.js (fjs)

functional.js is a functional JavaScript library.

It facilitates currying and point-free / tacit programming, with optional lambda expressions.

Documentation

Visit functionaljs.com for the full documentation including curry, each, map, reduce, fold, apply, every, any, select, pluck, toArray, first, last, best, partition, group, while and more.

Curry function example

var add = fjs.curry(function(a, b) {
    return a + b;
});

var add3 = add(3);

add(1, 2, 3); // => 6
add3(1, 2, 3, 4, 5); // => 18

Curry expression example

var add = fjs.curry("a, b => a + b");

var add3 = add(3);

add(1, 2, 3); // => 6
add3(1, 2, 3, 4, 5); // => 18

Curry ES6 example

const add = fjs.curry((a, b) => a + b);

const add3 = add(3);

add(1, 2, 3); // => 6
add3(1, 2, 3, 4, 5); // => 18

Real world example

var converter = fjs.curry(function(rate, symbol, input) {
    var output = input * rate;
    return symbol + output.toFixed(2);
});

var poundsToUSD = converter(1.52, "$");
var poundsToEUR = converter(1.27, "€");

poundsToUSD(100); // => "€63.50"
poundsToEUR(50); // => "$152.00"

License

MIT License