JavaScript组合模式

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

var square = function(a) {
    return a * a;
};

var combine = function(fnA, fnB) {
    return function() {
        var args = Array.prototype.slice.call(arguments);
        var result = fnA.apply(null, args);
        return fnB.call(null, result);
    }
};

var addThenSquare = combine(add, square);

var result = addThenSquare(3, 5);
console.log(result); // 64