네이티브 JS에서 플러그인을 캡슐화하는 방법

//SetStyles.js
(function(win, doc) {
    var defaultSettings = {
        color: "red",
        background: "blue",
        border: "2px solid #000",
        fontSize:"30px",
        textAlign:"center",
        width:"200px",
        borderRadius:"5px"
    };
    function SetStyles(options) {
        var self = this;
        //没传配置项自己丢错
        if(!options) {
            throw new Error("请传入配置参数");
        }
        self = Object.assign(self, defaultSettings, options);
        self.container = doc.querySelector(self.container) || doc.querySelectorAll(self.container);
        self._changeStyles();
    }
    SetStyles.prototype = {
        _changeStyles: function() {
            var self = this;
            for(var pro in self) {
                if(pro == "container") {
                    continue;
                }
                if(pro == 'text' && typeof self[pro]== 'string') {
                    self.container.innerText = self[pro];
                    continue;
                }else if(pro == 'text' && typeof self[pro]== 'function'){
                    self.container.innerText = self[pro]();
                    continue;
                }
                self.container.style[pro] = self[pro];
            }
        }
    }
    win.SetStyles = SetStyles;
})(window, document)
  //调用
    var a = new SetStyles({
            container:"#test",
            background:"#fff",
            textAlign:"center",
            text:function(){
                return "我是文本";
            }
        });    //text参数格式字符串或者函数
    //container用的querySelectAll方法，参数一致
    //其他css参数为字符串