请问如何简化这种写法-我爱小程序

问题模块	框架类型	问题类型	操作系统	工具版本
开发者工具	小程序	需求	Windows	1.02.1902010

//对于js中很有规律的如下片段：

Txt={}

if (Knowledge[TabID].content0 != undefined) { Txt.Content0 = "x" + Knowledge[TabID].content0 + "\n" } else { Txt.Content0 =""}

if (Knowledge[TabID].content1 != undefined) { Txt.Content1 = "x" + Knowledge[TabID].content1 + "\n" } else { Txt.Content1 = "" }

if (Knowledge[TabID].content2 != undefined) { Txt.Content2 = "x" + Knowledge[TabID].content2 + "\n" } else { Txt.Content2 = "" }

if (Knowledge[TabID].content3 != undefined) { Txt.Content3 = "x" + Knowledge[TabID].content3 + "\n" } else { Txt.Content3 = "" }

if (Knowledge[TabID].content4 != undefined) { Txt.Content4 = "x" + Knowledge[TabID].content4 + "\n" } else { Txt.Content4 = "" }

if (Knowledge[TabID].content5 != undefined) { Txt.Content5 = "x" + Knowledge[TabID].content5 + "\n" } else { Txt.Content5 = "" }

// 如何简化写法？

拾忆：

var Txt = {

content0: "",

content1: "",

content2: ""

}

for(var key in Txt){

Txt[key] = Knowledge[TabID][key] ? "x" + Knowledge[TabID].content0 + "\n" : ''

}

凤凰县铭锋计算机科技有限公司：

写function函数简化

请问如何简化这种写法