How do I construct a regex string in Javascript using variables

Question

I've found similar questions and, thanks to those question, I think I've come close, but this still isn't doing what I want. (JQuery is already in use on this project, so I'm using it too.)

The snippet, as saved, works. If I comment out the current replace line and un-comment the one that's currently a comment, It seems to do nothing. It's supposed to find the first maxWordschars characters from the text, and any characters up to the next space and replace the string with what has been found.

  $('.practice').each(function(){
      var maxWordschars = 34;
      var strippedString = $(this).text().trim();        
      var regexpattern = new RegExp("/^(.{" + maxWordschars + "}[^\s]*).*/");
      var newString = strippedString.replace(/^(.{34}[^\s]*).*/, "$1");
      //var newString = strippedString.replace(regexpattern, "$1");
      if (newString != strippedString){
        newString += "...";
      }      
      $(this).text(newString);
  });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="practice">
  Let this be a long string of text that my script has to deal with to make it fit.
</div>
<br>
<div class="practice">
  Allow this considerably longer paragraph of text with multisylable enunciations to further quantify the effectiveness of my script
</div>

TecBrat · Accepted Answer · 2017-03-30 20:27:15Z

4

var regexpattern = new RegExp("^(.{" + maxWordschars + "}\\S*).*");

  $('.practice').each(function(){
      var maxWordschars = 34;
      var strippedString = $(this).text().trim();        
      var regexpattern = new RegExp("^(.{" + maxWordschars + "}\\S*).*");
      //var newString = strippedString.replace(/^(.{34}[^\s]*).*/, "$1");
      var newString = strippedString.replace(regexpattern, "$1");
      if (newString != strippedString){
        newString += "...";
      }      
      $(this).text(newString);
  });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="practice">
  Let this be a long string of text that my script has to deal with to make it fit.
</div>
<br>
<div class="practice">
  Allow this considerably longer paragraph of text with multisylable enunciations to further quantify the effectiveness of my script
</div>

edited Mar 30, 2017 at 20:27

TecBrat

3,7353 gold badges31 silver badges49 bronze badges

answered Mar 30, 2017 at 20:16

MypKOT-1992

1913 bronze badges

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2 Comments

TecBrat Over a year ago

I found that \\w* works as well as \\S* and syntactically is what I really want to do. (Match word characters instead of matching non-space characters.)

MypKOT-1992 Over a year ago

\w === [a-zA-Z0-9_] 'my $a here'.replace(/^(.{3}\w*).*/, '$1...') // my ... 'my $a here'.replace(/^(.{3}\S*).*/, '$1...') // my $a...

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