Question

I have this regex variable:

var regexp = new RegExp(RegExp.quote(myExpression) + '\\b', 'g');

which searches for expression that has a space after it. (RegExp.quate() I got from this How to escape regular expression in javascript?)

I want to search for it only outside curly brackets.

so if I myExpression = "cat"

and I have this string:

the cat { is cat { and } cat {and { another cat } } and  cat } and another cat
    ^^^                                                                    ^^^

I want to get a match only for the first cat and the last cat – I don’t want any match for anything inside the outer curly brackets.

I found some regex for this but non of them worked as I hoped for.

what do I need to write to get it done?

thanks,
Alon

Answer 1

Something like this problem of matching nested brackets is not possible to solve using a single regex. Here is my take to resolve your problem:

var myExpression = "cat";
var s = 'the cat {is cat { and} cat {and { another cat}}and  cat } and another cat';
arr = s.split(/(?=(?:\b|\W))\s*/g);
document.writeln("<pre>split: " + arr + "</pre>");
//prints: the,cat,{,is,cat,{,and,},cat,{,and,{,another,cat,},},and,cat,},and,another,cat
var level=0;
for (i=0; i<arr.length; i++) {
  if (level == 0 && arr[i] == myExpression)
     document.writeln("<pre>Matched: " + arr[i] + "</pre>");
  if (arr[i] == "{")
     level++;
  else if (arr[i] == "}")
     level--;
}