请问js这段具体什么问题

[lzh1104]

http://alloyteam.github.io/CodeGuide/#js-jshint 这个下边

// not good
var singleton = new function() {
    var privateVar;

    this.publicMethod = function() {
        privateVar = 1;
    };

    this.publicMethod2 = function() {
        privateVar = 2;
    };
};

请给出建议写法，，