text: function convertThousands(string) {
    const pattern = /\B(?=(\d{3})+(?!\d))/g;
    const thoundsands = string.toString().replace(pattern, ',');
    return thoundsands;
  }
  
  /*  
    x(?y) matches x only if x is followed by y
    x(?!y) matches x only if x is not followed by y
    we nested the last one in the first one
    \b matches position whrere *a word character* is not followed or preceded by another word-character
     hello
    |     |
    \B means ~\b
    h e l l o
     | | | |
  */
  module.exports = convertThousands;