Posted in Javascript onNovember 21, 2011
接口+继承+代码优化思想
先分享下我觉得一个很不错的js编程小技巧,达到很大的代码共用性! 因为很多js库会在原生的对象上进行直接原型扩展,但这是很不好的习惯,不仅加重了每个新实例对象的内存消耗,而且容易造成污染性误解(以为有这东西)!而这也是建js库一个准则:尽量少的原型扩展,特别是越根部的对象!
js建库准则
js建库准则(Dean Edwards在开发base2时候的一些体会)翻译版:http://biaoge.me/2009/12/239 js建库学习好地方:http://ejohn.org/blog/building-a-javascript-library/ 假如你有时间,再看一个建js库超级前沿的文档,包括css3,浏览器最新API(如querySelector) build-a-javascript-framework
用继承提高代码共用性
因为不在原生对象上进行扩展,所以需要一个对外的命名空间,而在这个对象下会有一些接口供外部调用,而为了提高本身js库的健壮性,需要在最大程度减小对外接口(最理想的就是只保存用户需要的接口)! 那么这里便有一个问题,我将它实例化吧:
var namespace={ IOfirst:function(){}, IOsecond:function(){} }
在对象namespace下有个东西需要给IOfirst跟IOsecond共用,而又不想暴露这个接口! 我是通过继承将所有对外接口通过一个父接口包装,然后在一个init方法下统一赋值,而在init这方法下,由于闭包的作用,达到了代码的共用性! 具体做法:
动态添加对外接口,加强代码灵活性
addIO:function(str){ var arrs = str.split("."), o = this; for (i=(arrs[0] == "Date$") ? 1 : 0; i0) { var data=arrs[0] o[arrs[i]]=o[arrs[i]] ||function(){return this.parIO.apply(null,[data,arguments])}; o=o[arrs[i]]; } } InitFuns:function(){ var that=this; var funs=this.actionFun; //init interface for all functions(test successfully) var interfaces=["testLeap","disDayNum","todayBetween","getMonthByDay","getNextWeekByDay","getWeekByDay","newDate","compareDate"] var shift; do{ shift=interfaces.shift() that.addIO(shift); funs[shift]=function(){}; }while(interfaces.length>0) //set the common object and variable //for browers test var br={ ie:false,//IE6~8 ff:false,//Firefox ch:false//Chrome } var nav=navigator.userAgent; if(!-[1,]) br.ie=true; else if(nav.indexOf("Firefox")>0) br.ff=true; else if(nav.indexOf("Chrome")>0) br.ch=true; //continue to set IO }
在控制台上输出初始化完成的接口:
于是所有对外接口都绑定到parIO下面,这样在有很多接口的情况下可以少敲好多代码哦! 而关键的维系内外部枢纽的parIO负责找到子接口,传参,并返回
parIO:function(){ if(Date$.actionFun[arguments[0]]) { var customFun=Date$.actionFun[arguments[0]] return customFun.apply(null,[arguments[1]]); } else console&&cosnole.log("empty"); },
而可以看到有三部分:
在 //set the common object and variable 那里我们可以写我们的公用函数,变量,如判断浏览器,加入类似后台的sqlHelp 函数 之后便是初始化接口了:
funs.newDate=function(){ return formatDate(arguments[0][0]) } funs.getWeekByDay=function(){ return getWeekByDay(arguments[0][0]); } funs.getNextWeekByDay=function(){ var speDate=formatDate(arguments[0][0]); speDate.setDate(speDate.getDate()+7); return getWeekByDay(speDate); }
而且这样还有一个好处,就是你的代码不会给人家随便的复制去用,因为接口的内部联系性很大!例如上面的funs.getWeekByDay,funs.getNextWeekByDay公用了getWeekByDay()方法! 最后附上我的不成熟的js库以及接口声明,还望大牛帮忙改进下,万分感谢
/* //function:to compare two dates and return information "equal"/"more"/"less" //arguments num:2 //arguments type: Date,Date //arguments declaration:1.the target object you need to compare(Subtrahend);2.the compare object(Minuend) //return data -- type: String ; three value: "more"(if target is larger),"equal"(if target is equal to compared object),"less"(if target is smaller) compareDate:function (objDate,comDate) { }, //function:to format the string to Date ,and return //arguments num:1 //arguments type: for this interface apply for overload , so String or Date is allowed //arguments declaration:if you pass String ,it should format to "YYYY-MM-DD" or "YYYY/MM/DD" or "YYYY:MM:DD" like "2008/10/12" //return date : type:Date;one value:the date you want after formatting newDate :function (str) { }, //function:get the start date and end date of the week of the date you have passed and return the Json including {startDay,endDay} //arguments num:1 //arguments type:for this interface apply for overload , so String or Date is allowed //arguments declaration:the day you want to get the first day and last day of in this weeek;if you pass String ,it should format to "YYYY-MM-DD" or "YYYY/MM/DD" or "YYYY:MM:DD" like "2008/10/12" //return data--type :Json ; one value:{startDay:"",endDay:""} ,you can get it by var.startDay(var is your custom variable) getWeekByDay :function (day) { }, //function:get the start date and end date of next week of the date you have passed and return the Json including {startDay,endDay} //arguments num:1 //arguments type:for this interface apply for overload , so String or Date is allowed //arguments declaration:the day you want to get the first day and last day of in this weeek;if you pass String ,it should format to "YYYY-MM-DD" or "YYYY/MM/DD" or "YYYY:MM:DD" like "2008/10/12" //return data--type :Json ; one value:{startDay:"",endDay:""} ,you can get it by var.startDay(var is your custom variable) getNextWeekByDay :function (day) { }; //function:get the start date and end date of the month of the date you have passed and return the Json including {startDay,endDay} //arguments num:1 //arguments type:Date //arguments declaration:the day you want to get the first day and last day of in this month //return data--type :Json ; one value:{startDay:"",endDay:""} ,you can get it by var.startDay(var is your custom variable) getMonthByDay :function (day) { }, //function:to test if including today between the two dates you pass and return in boolean //arguments num:2 //arguments type:Date,Date //arguments declaration:the procedure will test the larger and sort automatically ,so the order is no matter //return data-- type: boolean ; one value :true if today is between the two dates todayBetween :function (startDate,endDate) { }, //function:to caculate the difference between two dates in days //arguments num:2 //arguments type:Date,Date //arguments declaration:1.startDate(the one be reduced) 2.endDate(the one to reduce) //return data--type:Number ; one value:the different between these two dates disDayNum:function (startDate,endDate) { }, //function:test the year of the date you have passed leap or not and return in boolean //arguments num:1 //arguments type: for this interface apply for overload , so String or Date is allowed //arguments declaration:if you pass String ,it should format to "YYYY-MM-DD" or "YYYY/MM/DD" or "YYYY:MM:DD" like "2008/10/12" //return data -- type:boolean ;one value: true if it is leap year or false testLeap :function (date) { } */
欢迎下载:Date$.js
日期处理的js库(迷你版)--自建js库总结
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