code: function checkValue(i) {
    const start = i;
    let l;
    let s;
    let _i;
  
    while (i < tokensLength) {
      if (checkDeclDelim(i)) break;
  
      s = checkSC(i);
      _i = i + s;
  
      if (l = _checkValue(_i)) i += l + s;
      if (!l || checkBlock(i - l)) break;
    }
  
    tokens[start].value_end = i;
  
    return i - start;
  }
docs: Check if token is part of a value
  @param {Number} i Token's index number
  @returns {Number} Length of the value