不带<a>标签的正则</a>表达式匹配网址<a>-JS</a>

Question

I am looking for a regex expression in JavaScript for the same use case as this post here: regex matching links without <a> tag

My goal is to transform a string such as

Here is a link https://www.somewebsite.com/ here is a link already in an a tag <a href="https://www.somewebsite.com/">https://www.somewebsite.com/</a>

To

Here is a link <a href="https://www.somewebsite.com/">https://www.somewebsite.com/</a> here is a link already in an a tag <a href="https://www.somewebsite.com/">https://www.somewebsite.com/</a>

There are many regex examples for a url, but I am not sure how to add an "and" condition for the url match not being in an <a> tag. I have only found examples so far for php or python, but not JS.

Thank you!

Answer 1

Instead of using regex, you can test the URL that was supplied to see if it is treated as an external resource. Here, I split the string by whitespace, then tested each part to see if it is a defined URL.

 const string = `Here is a link https://www.somewebsite.com/ here is a link already in an a tag <a href="https://www.somewebsite.com/">https://www.somewebsite.com/</a>`; const newString = string .split(/\\s+/) .map(string => (isDefinedUrl(string)) ? makeUrl(string) : string) .join(' '); console.log(newString); function isDefinedUrl(possibleUrl) { const a = document.createElement('a'); a.href = possibleUrl; return (possibleUrl === a.href); } function makeUrl(url) { return `<a href="${url}">${url}</a>`; }