JavaScript中是否有一个"not in"运算符来检查对象属性? [英] Is there a “not in” operator in JavaScript for checking object properties?

问题描述

JavaScript中是否存在某种不存在"运算符来检查对象中是否不存在属性?我在Google或Stack Overflow上找不到任何相关信息.这是我正在研究需要这种功能的一小段代码:

Is there any sort of "not in" operator in JavaScript to check if a property does not exist in an object? I couldn’t find anything about this around Google or Stack Overflow. Here’s a small snippet of code I’m working on where I need this kind of functionality:

var tutorTimes = {};

$(checked).each(function(idx){
  id = $(this).attr('class');

  if(id in tutorTimes){}
  else{
    //Rest of my logic will go here
  }
});

如您所见，我会将所有内容放入else语句中.对于我来说，仅仅使用else部分来设置if – else语句对我来说似乎是错误的.

As you can see, I’d be putting everything into the else statement. It seems wrong to me to set up an if–else statement just to use the else portion.

推荐答案

设置if/else语句仅使用else部分对我来说似乎是错误的...

It seems wrong to me to set up an if/else statement just to use the else portion...

只需取消条件，您就会在if中获得else逻辑:

Just negate your condition, and you'll get the else logic inside the if:

if (!(id in tutorTimes)) { ... }

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