Regex replacing couples of symbols by HTML tags

I'm trying to build a regex to replace all the couples of symbols "$$" with some HTML tag, say, <someTag></someTag>.

I use this regular expression but it doesn't cover all the cases:

$$(\S[^\*]+\S)$$

'aaa $$123$$ c$ ddd'.replace(/$$(\S[^\*]+\S)$$/g, '<a1>$1</a1>') // works

'aaa $$123$$ c$ $$ddd$$'.replace(/$$(\S[^\*]+\S)$$/g, '<a1>$1</a1>') // doesn't work, should be 'aaa <a1>123</a1> c$ <a1>ddd</a1>'

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

console.log('aaa $$123$$ c$ ddd'.replace(/$$(\S[^\*]+\S)$$/g, '<a1>$1</a1>')) // works

console.log('aaa $$123$$ c$ $$ddd$$'.replace(/$$(\S[^\*]+\S)$$/g, '<a1>$1</a1>')) // doesn't work, should be 'aaa <a1>123</a1> c$ <a1>ddd</a1>'

<!-- end snippet -->

</details>


# 答案1
**得分**: 1

这是一个用于替换标记的 JavaScript 函数。它会根据指定的分隔符 `$$` 将字符串拆分，然后根据当前索引是奇数还是偶数来添加开放标记 (`prefix`) 或闭合标记 (`suffix`)，最后返回替换后的字符串。希望这有所帮助！

<details>
<summary>英文:</summary>

Not a regex solution, but this works. Explanation: Split the string using your delimiter (`$$`). Then create a new string `result` and insert each part of the array. Then check if the current index is odd or even and depending on that add either the opening tag (`prefix`) or the closing tag (`suffix`). I hope this helps!


&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    function replaceTag(string, delimiter, prefix, suffix){
      
      let parts = string.split(delimiter);
      let result = &#39;&#39;;
      
      for(let index = 0; index &lt; parts.length; index++){
      
        result += parts[index];
      
        if(index % 2 == 0 &amp;&amp; index &lt; parts.length - 1){
        
          result += prefix;
        
        }
        else if(index &lt; parts.length - 1){
        
          result += suffix;
        
        }
      
      }
      
      return result;

    }

    console.log(replaceTag(&#39;aaa $$123$$ c$ ddd&#39;, &#39;$$&#39;, &#39;&lt;my-tag&gt;&#39;, &#39;&lt;/my-tag&gt;&#39;));
    console.log(replaceTag(&#39;aaa $$123$$ c$ $$ddd$$&#39;, &#39;$$&#39;, &#39;&lt;my-tag&gt;&#39;, &#39;&lt;/my-tag&gt;&#39;));

&lt;!-- end snippet --&gt;



</details>



# 答案2
**得分**: 1

问题在于你的正则表达式匹配方式是“贪婪匹配”，这意味着它会匹配字符串中尽可能多的部分。要使其成为“非贪婪匹配”，你需要添加`?`作为“懒惰量词”。我建议使用以下正则表达式：

```javascript
const regex = /$$(\w+?)$$/g

它会匹配两个$符号，然后至少一个单词字符。

const regex = /$$(\w+?)$$/g

答案3

得分: 1

以下是已翻译的内容：

纯正则表达式解决方案如下：

$$((?:(?!$$).)+)$$

其中 ((?:(?!\$\$).)+) 部分（也称为受限贪婪标记）将匹配除了 $$ 之外的任何内容，并且你要查找的内容将被捕获在第一个组中，然后你可以轻松地将它放入你想要的标签中。

这个正则表达式甚至允许你捕获单个 $，如果它出现在内容中，而且即使你的内容跨越多行，也可以工作，你可以将 . 替换为 [\w\W] 或根据你的字符匹配需求将 . 更改为其他内容。

演示

$$((?:(?!$$).)+)$$

答案4

得分: 1

你可以使用 /\$\$(\S+)\$\$/g。

这确保了成功匹配需要在两组 "$$" 之间有任意数量的字符，而没有空格。

const str = 'aaa $$123$$ $$c$ $$x $$ $$ddd$$';
const rgx = /$$(\S+)$$/g;
const sub = '<a1>$1</a1>';

const res = str.replace(rgx, sub);

console.log(res);

const str = 'aaa $$123$$ $$c$ $$x $$ $$ddd$$';
const rgx = /$$(\S+)$$/g;
const sub = '<a1>$1</a1>';

const res = str.replace(rgx, sub);

console.log(res);

答案5

得分: 1

The fastest way is to use the non greedy dot-all approach: /\$\$(.*?)\$\$/sg
https://regex101.com/r/upveAX/1
Using the Dot alone will always be faster since it doesn't rely on assertion or class structures, which add 3 times more overhead in performance.

Should you choose to not use the Dot approach, you run the risk of orphaned $$ in your text as the regex mainly expect pairs of $$..$$.

console.log('aaa $$123$$ c$ ddd'.replace(/$$(.*?)$$/sg, '<a1>$1</a1>'));

console.log('aaa $$123$$ c$ $$ddd$$'.replace(/$$(.*?)$$/sg, '<a1>$1</a1>'));