编程基础设计原则开闭

1、Softwareentities(classes,modules,functions,etc.)shouldbeopen for extenlosed for modification.open for exten模型达到目的。而Close for modification（对修改关闭）的意思是说不允许对该实体做任 HYPERLINK http:/f/ varAnswerType Choice: Input: functionquestion(label,answerType, return label: label, : var view = (function () renderfunct

2、ion , question) varquestionWrapperame = varquestionLabel= var label =ame = question-label;varanswer= ame = question-input;if (question.answerType = AnswerType.Choice) inputlen = (vari=0;i var option = option.textvarquestionLabel= var label =ame = question-label;varanswer= ame = question-input;if (qu

3、estion.answerType = AnswerType.Choice) inputlen = (vari=0;i var option = option.text= len; i+) option.value=question.choi else (question.answerType=input input.type = return (vari(, questions) 0;iquestions.length;, var questions question(Have you used tobacco last30 days?, AnswerType.Choice, Yes, qu

4、estion(Whatmedicationsareyoucurrentlyquestion(Whatmedicationsareyoucurrentlyusing?, var questionRegion =view.render(questionRegion, questions);上面的代码，viewrenderquestion 列表，展示的时候根据 choi 的选项（如果是选择类型的话）Choice 那就根据选项生产一个下拉菜单，如果类型是 Input，那就简单地展示 input 输入框。 uestion 里的条件语句，这明显 了开闭原则。ender 能力，而不需要修改view 对象先来

5、创建一个通用的questionCreatorfunctionquestionCreator(spec, t = my = my | ; my.label=spec.label;my.renderInput=function throw not t.render = function ) var questionWrapper =var questionLabel =ame = question-label;var label =var answer = /因为不/因为不 return questionWrapper;是rnr的rnrnpt方法以其他ncion可以盖，以用不同类，继续看一每个问类

6、型的现代function choiceQuestionCreator(spec) var my = t = questionCreator(spec, my.renderInput = function () var input =var len = spec.choifor (var i = 0; i len; i+) var option =option.text = spec.choioption.value = spec.choireturn function var my = t = questionCreator(spec, my.renderInput = function ()

7、 varinputinput.type = 功能delegat给针对每个问题类型的扩展代码renderInput上2. spec属性替换掉了前面question return choiceQuestionCreatorinputQuestionCreatorinput输入renderInput 实现，通过 调用 的 questionCreator(spec, my)然后返回 t 对var view = render: , questions) for (var i = 0; i questions.length; var questions label: Have you used tobacco products withhelast30days?, : Yes, Nolabel:What medications are you currently var questionRegion view.render(questionRegion, 重构以后的版本的 重构以后的版本的 view 对象可以