The Unheralded Perspective

function createBuglink(str) {
  //Create buglink
  var matchFound = new Boolean(false);
  var bugInDesc = 0;
  var pattern = -1;
  var bugLink = "";
 
  re = new RegExp("[bB][uU][gG]\\s\\d\{6\}");
  re2 = new RegExp("b=\\d\{6\}");
  re3 = new RegExp("\\d\{6\}\\W");
 
  bugInDesc = str.search(re);
  if(bugInDesc != -1) {
    matchFound = true;
	pattern = 1;
  } else {
      bugInDesc = str.search(re2);
	  if(bugInDesc != -1) {
	    matchFound = true;
	    pattern = 2;
	  } else {
	      bugInDesc = str.search(re3);
	      if(bugInDesc != -1) {
	        matchFound = true;
		    pattern = 3;
		  }
	  }
  }
 
  if(matchFound == true) {
    if(pattern == 1) {
	  bugLink = bugLinkify(bugInDesc, str, 4, 10);
	} else if(pattern == 2) {
	  bugLink = bugLinkify(bugInDesc, str, 2, 8);
    } else if(pattern == 3) {
	  bugLink = bugLinkify(bugInDesc, str, 0, 6);
    }	
  } else { //No bug provided
      bugLink = str;
    }
 
  return bugLink;
}

function bugLinkify(bugInDesc, str, start, end) {
  var bugLinkName = str.substring(bugInDesc, bugInDesc + end);
  var bugNumber = bugLinkName.substring(start, end);
  var bugLink = 
    str.substring(0, bugInDesc) + 
    '<a href=\"https://bugzilla.mozilla.org/show_bug.cgi?id=' + 
    bugNumber + 
    '\">' + 
    bugLinkName + 
    '</a>' + 
    str.substring(bugInDesc + end, str.length);
 
  return bugLink;
}