blocks|key|694203|text|您可以使用try/catch和RegExp构造函数：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|694204|var+isValid+=+true;
try+{
++++new+RegExp("the_regex_to_test_goes_here");
}+catch(e)+{
++++isValid+=+false;
}

if(!isValid)+alert("Invalid+regular+expression");|code-block|syntax|javascript|694205|entityMap^0|5|9|F|6|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

<p>You can use <code>try/catch</code> and the <code>RegExp</code> constructor:</p>

<pre><code>var isValid = true;
try {
    new RegExp("the_regex_to_test_goes_here");
} catch(e) {
    isValid = false;
}

if(!isValid) alert("Invalid regular expression");
</code></pre>


blocks|key|4145830|text|下面是一个小函数，用于检查两种类型的正则表达式、字符串或模式的有效性：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4145831|function+validateRegex(pattern)+{
++++var+parts+=+pattern.split('/'),
++++++++regex+=+pattern,
++++++++options+=+"";
++++if+(parts.length+>+1)+{
++++++++regex+=+parts[1];
++++++++options+=+parts[2];
++++}
++++try+{
++++++++new+RegExp(regex,+options);
++++++++return+true;
++++}
++++catch(e)+{
++++++++return+false;
++++}
}|code-block|syntax|javascript|4145832|例如，用户将能够同时测试test和/test/g。Here是一个有效的小提琴。|offset|length|style|CODE|4145833|entityMap|0|LINK|mutability|MUTABLE|url|http://jsfiddle.net/nmuzx/^0|0|0|C|4|H|7|P|4|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@$I|X|J|Y|K|L]|$I|Z|J|10|K|L]]|9|@$I|11|J|12|1|13]]|A|$]]|$1|M|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

<p>Here is a little function that checks the validity of both types of regexes, strings or patterns:</p>

<pre><code>function validateRegex(pattern) {
    var parts = pattern.split('/'),
        regex = pattern,
        options = "";
    if (parts.length &gt; 1) {
        regex = parts[1];
        options = parts[2];
    }
    try {
        new RegExp(regex, options);
        return true;
    }
    catch(e) {
        return false;
    }
}
</code></pre>

<p>The user will be able to test both <code>test</code> and <code>/test/g</code> for example. <a href="http://jsfiddle.net/nmuzx/" rel="noreferrer">Here</a> is a working fiddle.</p>


blocks|key|2020970|text|function+isRegExp(regExp){
++++++++++try+{
++++++++++++++++new+RegExp(regExp);
++++++++++++++}+catch(e)+{
++++++++++++++++return+false
++++++++++++++}
+++++++++return+true
++++}

ex:
isRegExp(/@(\w%2B)/g)+=+true|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|2020971|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>function isRegExp(regExp){
          try {
                new RegExp(regExp);
              } catch(e) {
                return false
              }
         return true
    }

ex:
isRegExp(/@(\w+)/g) = true
</code></pre>


blocks|key|2021010|text|此函数可以将'/‘字符作为正则表达式中的普通字符来处理，也可以考虑在是普通字符串时进行转义。它将总是返回一个正则表达式，如果不是一个好的正则表达式字符串，则返回null。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2021011|​|2021012|function+getRegex(regex)+{
++++try+{
++++++++regex+=+regex.trim();
++++++++let+parts+=+regex.split('/');
++++++++if(regex[0]+!==+'/'+%7C%7C+parts.length<+3){
++++++++++regex+=+regex.replace(/[.*%2B\-?%5E${}()%7C[\]\\]/g,+'\\$&');+//escap+common+string
++++++++++return+new+RegExp(regex);
++++++++}

++++++++const+option+=parts[parts.length+-+1];
++++++++const+lastIndex+=+regex.lastIndexOf('/');
++++++++regex+=+regex.substring(1,+lastIndex);
++++++++return+new+RegExp(regex,+option);
++++}+catch+(e)+{
++++++++return+null
++++}
}

console.log(getRegex('ab/c'))
let+htmlStartTag+=+getRegex('/<(?!/)(?!br)(.%2B?)(?<!/)>/mgs');
console.log(htmlStartTag)
let+result+=+`</button><input+id="warehouse-search-field-tablet"
class="form-control+search-field"
+title="Warehouse+Search+Field"+name="location"+type="search"+value="">content`.matchAll(htmlStartTag);
+console.log([...result])|code-block|syntax|javascript|2021013|2021014|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|N|8|@]|9|@]|A|$G|H]]|$1|I|3|C|5|6|7|O|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|P|8|@]|9|@]|A|$]]]|K|$]]

<p>this function could handle the '/' char as a normal char in regex, and also consider escaping when is a common string. it will always return an Regex, null if not a good regex string.</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>function getRegex(regex) {
    try {
        regex = regex.trim();
        let parts = regex.split('/');
        if(regex[0] !== '/' || parts.length&lt; 3){
          regex = regex.replace(/[.*+\-?^${}()|[\]\\]/g, '\\$&amp;'); //escap common string
          return new RegExp(regex);
        }

        const option =parts[parts.length - 1];
        const lastIndex = regex.lastIndexOf('/');
        regex = regex.substring(1, lastIndex);
        return new RegExp(regex, option);
    } catch (e) {
        return null
    }
}

console.log(getRegex('ab/c'))
let htmlStartTag = getRegex('/&lt;(?!/)(?!br)(.+?)(?&lt;!/)&gt;/mgs');
console.log(htmlStartTag)
let result = `&lt;/button&gt;&lt;input id="warehouse-search-field-tablet"
class="form-control search-field"
 title="Warehouse Search Field" name="location" type="search" value=""&gt;content`.matchAll(htmlStartTag);
 console.log([...result])</code></pre>
</div>
</div>
</p>


blocks|key|694273|text|问题已经解决了，但如果有人需要定义字符串是有效的RegExp或根本不是RegExp。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|694274|如前所述，您可以在函数体中通过try+...+catch和new+RegExp()使用new+Function()和模板。|offset|length|style|CODE|694275|下面是一个带有解释的片段：|694276|​|694277|const+isRegExp+=+(string)+=>+{
++++try+{
++++++++return+new+Function(`
++++++++++++"use+strict";
++++++++++++try+{
++++++++++++++++new+RegExp(${string});
++++++++++++++++return+true;
++++++++++++}+catch+(e)+{
++++++++++++++++return+false;
++++++++++++}
++++++++`)();
++++}+catch(e)+{
++++++++return+false;
++++}
};

//+Here+the+argument+'simplyString'+shall+be+undefined+inside+of+the+function
//+Function(...)+catches+the+error+and+returns+false
console.log('Is+RegExp+valid:',+isRegExp('simplyString'));

//+Here+the+argument+shall+cause+a+syntax+error
//+isRegExp+function+catches+the+error+and+returns+false
console.log('Is+RegExp+valid:',+isRegExp('string+which+is+not+a+valid+regexp'));

//+Here+the+argument+is+not+a+valid+RegExp,+new+RegExp(...)+throws+an+error
//+Function(...)+catches+the+error+and+returns+false
console.log('Is+RegExp+valid:',+isRegExp('abc+([a-z]%2B)+([a-z]%2B))'));

//+Valid+RegExp,+passed+as+a+string
console.log('Is+RegExp+valid:',+isRegExp('/%5E[%5E<>()[\]\\.,;:\s@\"]$/'));

//+Valid+RegExp,+passed+as+a+RegExp+object
console.log('Is+RegExp+valid:',+isRegExp(/%5E[%5E<>()[\]\\.,;:\s@\"]$/));

//+Howewer,+the+code+injection+is+possible+here
console.log('Is+RegExp+valid:',+isRegExp(');console.log("This+is+running+inside+of+the+Function(...)+as+well"'));|code-block|syntax|javascript|694278|694279|entityMap^0|0|F|D|T|C|17|E|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@$D|V|E|W|F|G]|$D|X|E|Y|F|G]|$D|Z|E|10|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|11|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|12|8|@]|9|@]|A|$]]|$1|L|3|M|5|N|7|13|8|@]|9|@]|A|$O|P]]|$1|Q|3|K|5|6|7|14|8|@]|9|@]|A|$]]|$1|R|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|S|$]]

<p>The question is solved, but if someone needs to define is the string either valid <em>RegExp</em> or not a <em>RegExp</em> at all.</p>

<p>You can use <code>new Function()</code> and templating inside of the function body with <code>try ... catch</code> and <code>new RegExp()</code> as mentioned earlier.</p>

<p>There is a snippet with the explanations:</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>const isRegExp = (string) =&gt; {
    try {
        return new Function(`
            "use strict";
            try {
                new RegExp(${string});
                return true;
            } catch (e) {
                return false;
            }
        `)();
    } catch(e) {
        return false;
    }
};

// Here the argument 'simplyString' shall be undefined inside of the function
// Function(...) catches the error and returns false
console.log('Is RegExp valid:', isRegExp('simplyString'));

// Here the argument shall cause a syntax error
// isRegExp function catches the error and returns false
console.log('Is RegExp valid:', isRegExp('string which is not a valid regexp'));

// Here the argument is not a valid RegExp, new RegExp(...) throws an error
// Function(...) catches the error and returns false
console.log('Is RegExp valid:', isRegExp('abc ([a-z]+) ([a-z]+))'));

// Valid RegExp, passed as a string
console.log('Is RegExp valid:', isRegExp('/^[^&lt;&gt;()[\]\\.,;:\s@\"]$/'));

// Valid RegExp, passed as a RegExp object
console.log('Is RegExp valid:', isRegExp(/^[^&lt;&gt;()[\]\\.,;:\s@\"]$/));

// Howewer, the code injection is possible here
console.log('Is RegExp valid:', isRegExp(');console.log("This is running inside of the Function(...) as well"'));</code></pre>
</div>
</div>
</p>


blocks|key|694294|text|这里的答案都不能满足我检查字符串是否为其他语言(主要是php)的有效正则表达式的需要，因为它们要么忽略标志、分隔符，要么忽略转义的特殊字符，所以我编写了自己的函数|type|unstyled|depth|inlineStyleRanges|entityRanges|data|694295|​|694296|function+isValidRegex(s)+{
++try+{
++++const+m+=+s.match(/%5E([/~@;%25#'])(.*?)\1([gimsuy]*)$/);
++++return+m+?+!!new+RegExp(m[2],m[3])
++++++++:+false;
++}+catch+(e)+{
++++return+false
++}
}

console.log(isValidRegex('abc'))+//False
console.log(isValidRegex('/abc/'))+//True
console.log(isValidRegex('/ab#\/[c]/ig'))+//True
console.log(isValidRegex('@ab#\/[c]@ig'))+//Special+delimiters:+True
console.log(isValidRegex('/ab\/[c/ig'))+//False
console.log(isValidRegex('/abc/gig'))+//False|code-block|syntax|javascript|694297|694298|还可以派生此函数将字符串转换为RegExp对象|694299|694300|function+stringToRegex(s)+{
+++const+m+=+s.match(/%5E([/~@;%25#'])(.*?)\1([gimsuy]*)$/);
+++return+m+?+new+RegExp(m[2],+m[3])+:+new+RegExp(s);
}

console.log(stringToRegex('abc'))
console.log(stringToRegex('/abc/'))
console.log(stringToRegex('/ab#\/[c]/ig'))
console.log(stringToRegex('@ab#\/[c]@ig'))
try+{
++console.log(stringToRegex('/ab#\/[c/ig'))
}+catch+(e)+{
++console.log('Not+a+valid+regex')
}|694301|694302|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|T|8|@]|9|@]|A|$G|H]]|$1|I|3|C|5|6|7|U|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|V|8|@]|9|@]|A|$]]|$1|L|3|C|5|6|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|F|7|X|8|@]|9|@]|A|$G|H]]|$1|O|3|C|5|6|7|Y|8|@]|9|@]|A|$]]|$1|P|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|Q|$]]

<p>None of the answers here satisfied my need for checking that a string is a valid regex for other languages (Mostly php), because they either ignore the flags, the delimiters or escaped special characters, so I made my own function</p>
<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>function isValidRegex(s) {
  try {
    const m = s.match(/^([/~@;%#'])(.*?)\1([gimsuy]*)$/);
    return m ? !!new RegExp(m[2],m[3])
        : false;
  } catch (e) {
    return false
  }
}

console.log(isValidRegex('abc')) //False
console.log(isValidRegex('/abc/')) //True
console.log(isValidRegex('/ab#\/[c]/ig')) //True
console.log(isValidRegex('@ab#\/[c]@ig')) //Special delimiters: True
console.log(isValidRegex('/ab\/[c/ig')) //False
console.log(isValidRegex('/abc/gig')) //False</code></pre>
</div>
</div>
</p>
<p>You can also derive this function to transform a string into a RegExp object</p>
<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>function stringToRegex(s) {
   const m = s.match(/^([/~@;%#'])(.*?)\1([gimsuy]*)$/);
   return m ? new RegExp(m[2], m[3]) : new RegExp(s);
}

console.log(stringToRegex('abc'))
console.log(stringToRegex('/abc/'))
console.log(stringToRegex('/ab#\/[c]/ig'))
console.log(stringToRegex('@ab#\/[c]@ig'))
try {
  console.log(stringToRegex('/ab#\/[c/ig'))
} catch (e) {
  console.log('Not a valid regex')
}</code></pre>
</div>
</div>
</p>


<p>How do you check, in JavaScript, if a string is a proper regular expression that will compile? </p>

<p>For example, when you execute the following javascript, it produces an error.</p>

<pre><code>var regex = new RegExp('abc ([a-z]+) ([a-z]+))');
// produces:
// Uncaught SyntaxError: Invalid regular expression: /abc ([a-z]+) ([a-z]+))/: Unmatched ')'
</code></pre>

<p>How does one determine if a string will be a valid regex or not?</p>


How to check if the input string is a valid Regular expression?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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在JavaScript中，如何检查一个字符串是否是要编译的正确正则表达式？例如，当您执行以下javascript时，它会产生一个错误。var regex = new RegExp('abc ([a-z]+) ([a-z]+))');// produces:// Uncaught SyntaxError: Invalid...

问如何检查输入的字符串是否为有效的正则表达式？
EN

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问如何检查输入的字符串是否为有效的正则表达式？EN