countSubstringOccurrances

const countSubstringOccurrances = function(string, query) {
  let count = 0;
  while(string.includes(query)) {
    count++;
    let index = string.indexOf(query);
    string = string.slice(-(string.length-1-string.indexOf(query)));
  }
  return count;
};
  
countSubstringOccurrances('hello therell', 'll'); // => 2