composeVariadic.js

var compose = function compose(f) {
    var queue = f ? [f] : [];
    var fn = function fn(g) {
        if (arguments.length) {
            queue.push(g);
            return fn;
        }
        return function() {
            var args = Array.prototype.slice.call(arguments);
            queue.forEach(function(func) {
                args = [func.apply(this, args)];
            });
            return args[0];
        }
    };
    return fn;
};

composeVariadicTests.js

//------------------------------------------------------------------------------
var add1 = function(x) {return x + 1;};
var mult2 = function(x) {return x * 2;};
var square = function(x) {return x * x;};
var negate = function(x) {return -x;};
//------------------------------------------------------------------------------
 
var f = compose(add1)(mult2)(square)(negate)();
console.assert(-36, f(2), "f(2)");