关于coding中赋值运算和逻辑运算优先级的问题

Question

var isMonittor=(param.viewSetting?param.PageAccessMode:param.PageViewMode)||"Normal"=="Monitor"

上面这段代码在以下几种情况isMonittor的值
场景一

param.PageAccessMode = "acess";
param.PageViewMode = "view";
param.viewSetting = null;

场景二

param.PageAccessMode = "acess";
param.PageViewMode = "view";
param.viewSetting = "test";

场景三

param.PageAccessMode = null;
param.PageViewMode = "view";
param.viewSetting = null;

场景四

param.PageAccessMode = null;
param.PageViewMode = null;
param.viewSetting = null;

场景四中什么情况下(不加任何代码)可以先赋值"normal"再去做monitor

Answer 1

||、&& 可以理解短路运算符。
如果根据第一个元素就已知结果，那么就不会继续运算。

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var isMonittor=(param.viewSetting?param.PageAccessMode:param.PageViewMode)||"Normal"=="Monitor"

拆解一下

var isMonittor;
if(param.viewSetting){
    //param.PageAccessMode
    if(param.PageAccessMode){
        isMonittor=param.PageAccessMode
    }else{
        isMonittor="Normal"=="Monitor"
    }
}else{
    //param.PageViewMode
    if(param.PageViewMode){
        isMonittor=param.PageViewMode
    }else{
        isMonittor="Normal"=="Monitor"
    }
}