code: function pxValue(val, options) {
    if (!options) {
      options = {};
    }
  
    const baseFontSize = parseInt(prop(options, 'base-font-size', 16), 10);
  
    const value = parseFloat(val);
    const unit = val.replace(value, '');
    // eslint-disable-next-line default-case
    switch (unit) {
      case 'rem':
      case 'em':
        return value * baseFontSize;
      case 'pt':
        return value / (96 / 72);
      case 'px':
        return value;
    }
  
    throw new Error('The unit ' + unit + ' is not supported');
  }
docs: We only support rem/em/pt conversion
  @param val
  @param options
  @return {*}