Regex - check if input still has chances to become matching

Question

We\'ve got such regexp:

var regexp = /^one (two)+ three/;

So only string like \"one two three\" or \"one two three four\

Answer 1

I think there is no automatic "Apply to every Pattern"-Solution. However you can manually derive an "optional" pattern out of your regex, and check against both patterns:

var fullPattern = /^one (two)+ three/;
var optPattern = /^o?n?e? ?(t?w?o?)+ ?t?h?r?e?e?$/;

//verbal
if (fullPattern.matches()){
   //matched
} else {
  if (optPattern.matches()){
     //looks promising
  }else{
     //no match.
  }
}

You could also implement your own optionalizePattern() method, that converts Regex Pattern into such an Optional derivate. (Will be a difficult task to cover ALL possible patterns. Dunno, if possible at all.)