缓存代理模式

cacheProxy.js

    var mult = function() {
        console.log('开始计算乘积：');
        var a = 1;
        for (var i = 0, l = arguments.length; i < l; i++) {
            a = a * arguments[i];
        }
        return a;
    }

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

    var createProxyFactory = function(fn) {


        var cache = {};


        return function() {
            var args = Array.prototype.join.call(arguments, ',');
            if (args in cache) {
                return cache[args];
            }
            return cache[args] = fn.apply(this, arguments);
        }
    };
    var proxyMult = createProxyFactory(mult);

    var proxySum = createProxyFactory(sum);

    console.log(proxyMult(1, 2, 3, 4)) //24

    console.log(proxySum(2,3))