单体模式---静态属性中的实例

function Universe() {
        //缓存实例
        var instance = this;

        this.start_time = 0;
        this.bang = "Big";

        Universe = function(){
            return instance;
        };
    }

    //var uni = new Universe();
    //var uni2 = new Universe();
    //console.log(uni === uni2);


    Universe.prototype.nothing = true;

    var uni = new Universe();     //执行了一次 之后  Universe = function(){    return instance;};  断开了 prototype //Universe.prototype.nothing = true;

    Universe.prototype.everything = true;
    
    var uni2 = new Universe();

    console.log(uni.nothing);
    console.log(uni2.nothing);

    console.log(uni.everything);
    console.log(uni2.everything);

    console.log(uni.constructor.name);
    console.log(uni.constructor === Universe);