code: function checkCondition(i) {
    const start = i;
    let l;
    let _i;
    let s;
  
    if (i >= tokensLength) return 0;
  
    if (l = checkAtkeyword(i)) i += l;
    else return 0;
  
    if (['if', 'else'].indexOf(tokens[start + 1].value) < 0) return 0;
  
    while (i < tokensLength) {
      if (l = checkBlock(i)) break;
  
      s = checkSC(i);
      _i = i + s;
  
      if (l = _checkCondition(_i)) i += l + s;
      else break;
    }
  
    return i - start;
  }
docs: Check if token is part of a condition
  (e.g. `@if ...`, `@else if ...` or `@else ...`).
  @param {number} i Token's index number
  @return {number} Length of the condition