Javascript regex Pattern Match not working?-CodePudding

I plugged this together from various sources

<!--https://stackoverflow.com/questions/25413707/regex-for-youtube-channel-url-->
<body>
  <button onclick="writeytElement()">YTID</button>
  <script>
    function writeytElement() {
      //document.write("<div>Let's print an additional DIV here</div>");
      let str = 'https://www.youtube.com/user/SaphiraLynx';
      let pattern = '/(https?:\/\/)?(www\.)?youtu((\.be)|(be\..{2,5}))\/((user)|(channel))\/?([a-zA-Z0-9\-_]{1,})/';
      let matchs = str.match(pattern);
      matchs[9];
      document.write("<div>matchs</div>");

    }
  </script>
</body>


<!---pregmatch(UC[-_0-9A-Za-z]{21}[AQgw]);-->
<!--https://stackoverflow.com/questions/14366648/how-can-i-get-a-channel-id-from-youtube?rq=1-->

However it seems to malfunction. I.e. /no output/

Is this an issue of mine, or of the code (see commented section(s) ? (I might have mangled the variable in the document.write ...

But the script won't work still

CodePudding user response：

The issue is likely with the regex pattern, as it won't match the given string. Try using this regex instead:

/(https?:\/\/)?(www\.)?youtube\.com\/(channel|user)\/([a-zA-Z0-9\-_]{1,})/

CodePudding user response：

Remove the quotes from the pattern. Without quotes, it is a regex literal. With quotes, it is simply a string.

let str = 'https://www.youtube.com/user/SaphiraLynx';
// wrong
let pattern1 = '/(https?:\/\/)?(www\.)?youtu((\.be)|(be\..{2,5}))\/((user)|(channel))\/?([a-zA-Z0-9\-_]{1,})/';
let matchs1 = str.match(pattern1);
console.log(matchs1);
// right
let pattern2 = /(https?:\/\/)?(www\.)?youtu((\.be)|(be\..{2,5}))\/((user)|(channel))\/?([a-zA-Z0-9\-_]{1,})/;
let matchs2 = str.match(pattern2);
console.log(matchs2);

Also, if you want to embed variables within a string, consider using template literals:

document.write(`<div>${matchs}</div>`);