无效的正则表达式错误 [英] Invalid regular expression error

问题描述

我正在尝试检索此字符串 property_id = 516& category = featured-properties 的类别部分，因此结果应该是特色 - 属性，我想出了一个正则表达式并在这个网站上测试了它 http：// gskinner。 com / RegExr / ，它按预期工作，但是当我将正则表达式添加到我的javascript代码中时，我出现了无效的正则表达式错误，有人能告诉我这段代码搞乱了吗？

I'm trying to retrieve the category part this string "property_id=516&category=featured-properties", so the result should be "featured-properties", and I came up with a regular expression and tested it on this website http://gskinner.com/RegExr/, and it worked as expected, but when I added the regular expression to my javascript code, I had a "Invalid regular expression" error, can anyone tell me what is messing up this code?

谢谢！

var url = "property_id=516&category=featured-properties"
var urlRE = url.match('(?<=(category=))[a-z-]+');
alert(urlRE[0]);

推荐答案

积极的外观（你的？不符合ECMAScript 2018标准的JavaScript环境不支持< = ），这会导致您的RegEx失败。

Positive lookbehinds (your ?<=) are not supported in JavaScript environments that do not comply with ECMAScript 2018 standard, which is causing your RegEx to fail.

您可以通过一系列不同的方式模仿它们，但这可能是一个更简单的RegEx来完成工作：

You can mimic them in a whole bunch of different ways, but this might be a simpler RegEx to get the job done for you:

var url = "property_id=516&category=featured-properties"
var urlRE = url.match(/category=([^&]+)/);
// urlRE => ["category=featured-properties","featured-properties"]
// urlRE[1] => "featured-properties"

这是一个非常简单的例子，但是要搜索StackOverflow以解析RegEx模式如果您需要，URL参数将会显示更强大的示例。

That's a super-simple example, but searching StackOverflow for a RegEx pattern to parse URL parameters will turn up more robust examples if you need them.

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