code: function checkInclude(i) {
    let l;
  
    if (i >= tokensLength) return 0;
  
    if (l = checkInclude1(i)) tokens[i].include_type = 1;
    else if (l = checkInclude2(i)) tokens[i].include_type = 2;
  
    return l;
  }
docs: Check if token is part of an include (`@include` or `@extend` directive).
  @param {Number} i Token's index number
  @returns {Number}