docs: function normalize(value) {
    // Run this function for each item if value is array.
    if (value instanceof Array) {
      var output = [];
      for (var i = value.length; i--;) output[i] = normalize(value[i]);
      return output;
    }
  
    var number = strip(value);
    var unit = value.slice(number.length);
  
    // Truncate CSS number.
    number = parseFloat(number).toString();
    var extra = number.indexOf('0.');
    if (extra === 0) return number.slice(1) + unit;
    if (extra === 1 && number[0] === '-') return '-' + number.slice(2) + unit;
  
    // Return truncated number with unit.
    return number + unit;
  }