functional.js

var filter = require('prime/array/filter');
var slice = Array.prototype.slice;

var curry = function(fn){
    var args = slice.call(arguments, 1);
    return function(self){
        fn.apply(null, [self].concat(args);
    };
};

var modulo = function(n, i){
    return i % n;
};

var even = curry(modulo, 2);
var filterEven = curry(filter, even);

filterEven([1,2,3,4,5]); // [2,4]