javascript 使用三元运算符设置变量
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Using a ternary operator to set a variable
提问by Greg Wiley
I am trying to use a ternary operator to check if the value of an XML element is null. If it is then I want the variable to be one thing. If not then I would like it to return the value of element. This is what I have so far.
我正在尝试使用三元运算符来检查 XML 元素的值是否为空。如果是，那么我希望变量是一回事。如果没有，那么我希望它返回元素的值。这就是我迄今为止所拥有的。
var rating = data.getElementsByTagName("overall_average")[0].childeNodes[0].length > 0 ? data.getElementsByTagName("overall_average")[0].childeNodes[0].nodeValue : "It is empty";
采纳答案by jo_asakura
The shortest way:
最短的方法：
var rating = (data.getElementsByTagName('overall_average')[0].childNodes[0] || {}).nodeValue || 'It is empty';
回答by ?ime Vidas
Here:
这里：
var node = data.getElementsByTagName( 'overall_average' )[0].childNodes[0];
var rating = node ? node.nodeValue : 'It is empty';
Note that this code throws (an error) in case there is not a single "overall_average" element in data, so you might want to guard against that case if necessary...
请注意，如果 中没有单个“overall_average”元素，则此代码将引发（错误）data，因此您可能希望在必要时防范这种情况...
回答by Daniel Li
Your ternary operation look fine to me. One thing I would suggest (for readability and brevity) is to define your overall_averageobject as a variable and reference it after.
你的三元操作对我来说很好。我建议的一件事（为了可读性和简洁性）是将您的overall_average对象定义为变量并在之后引用它。
var overall_average = data.getElementsByTagName("overall_average")[0].childeNodes[0];
var rating = overall_average.length > 0 ? overall_average.nodeValue : "It is empty";
Good luck!
祝你好运！
