I found 4 projects which generate onion addresses. The fastest algorithm is in the project mkp244o. But it looks for addresses that contain words from a specified list. I don't need words in the address, I find it easier to remember a sequence of the same or repeated characters. I formed specific filtering rules and implemented them in javascript language, forwarded mkp244o -y stdout stream to nodejs. This caused a huge performance degradation.

function processAddress(hostname){
  let score = 0;
  let inrow = 0;
  for(let i = 1; i < 56; i++){
    if(hostname[i-1] == hostname[i]) {
      inrow += 2;
      score += inrow;
    } else {
      inrow = 0;
      if(i > 1){
        if(hostname[i-2] == hostname[i]){
          score += 1;
        }
      }
    }
  }
  return score;
}

I noticed the support for pcre. But, for unknown reason, I have no luck enabling it.
Probably a regular expression could be, for example /(?:([a-z2-7])\1{3,}.*){3,}/.

What should I do? I tried to understand the C code. But I don't understand any preprocessor directives.