code: function checkUnicodeRange(i) {
    const start = i;
    let l;
  
    if (i >= tokensLength) return 0;
  
    if (l = checkUrange(i)) i += l;
    else return 0;
  
    while (i < tokensLength) {
      const spaceBefore = checkSC(i);
      const comma = checkDelim(i + spaceBefore);
      if (!comma) break;
  
      const spaceAfter = checkSC(i + spaceBefore + comma);
      if (l = checkUrange(i + spaceBefore + comma + spaceAfter)) {
        i += spaceBefore + comma + spaceAfter + l;
      } else break;
    }
  
    return i - start;
  }
docs: Check if token is a unicode range (single or multiple <urange> nodes)
  @param {number} i Token's index
  @return {number} Unicode range node's length