source: frontend/node_modules/clean-css/lib/optimizer/validator.js

var functionNoVendorRegexStr = '[A-Z]+(\\-|[A-Z]|[0-9])+\\(.*?\\)';
var functionVendorRegexStr = '\\-(\\-|[A-Z]|[0-9])+\\(.*?\\)';
var variableRegexStr = 'var\\(\\-\\-[^\\)]+\\)';
var functionAnyRegexStr = '(' + variableRegexStr + '|' + functionNoVendorRegexStr + '|' + functionVendorRegexStr + ')';

var calcRegex = new RegExp('^(\\-moz\\-|\\-webkit\\-)?calc\\([^\\)]+\\)$', 'i');
var decimalRegex = /[0-9]/;
var functionAnyRegex = new RegExp('^' + functionAnyRegexStr + '$', 'i');
var hexAlphaColorRegex = /^#(?:[0-9a-f]{4}|[0-9a-f]{8})$/i;
// eslint-disable-next-line max-len
var hslColorRegex = /^hsl\(\s{0,31}[-.]?\d+\s{0,31},\s{0,31}\d*\.?\d+%\s{0,31},\s{0,31}\d*\.?\d+%\s{0,31}\)|hsla\(\s{0,31}[-.]?\d+\s{0,31},\s{0,31}\d*\.?\d+%\s{0,31},\s{0,31}\d*\.?\d+%\s{0,31},\s{0,31}\.?\d+\s{0,31}\)$/;
// eslint-disable-next-line max-len
var hslColorWithSpacesRegex = /^hsl\(\s{0,31}[-.]?\d+(deg)?\s{1,31}\d*\.?\d+%\s{1,31}\d*\.?\d+%\s{0,31}\)|hsla\(\s{0,31}[-.]?\d+(deg)?\s{1,31}\d*\.?\d+%\s{1,31}\d*\.?\d+%\s{1,31}\/\s{1,31}\d*\.?\d+%?\s{0,31}\)$/;
var identifierRegex = /^(-[a-z0-9_][a-z0-9\-_]*|[a-z_][a-z0-9\-_]*)$/i;
var namedEntityRegex = /^[a-z]+$/i;
var prefixRegex = /^-([a-z0-9]|-)*$/i;
var quotedTextRegex = /^("[^"]*"|'[^']*')$/i;
// eslint-disable-next-line max-len
var rgbColorRegex = /^rgb\(\s{0,31}[\d]{1,3}\s{0,31},\s{0,31}[\d]{1,3}\s{0,31},\s{0,31}[\d]{1,3}\s{0,31}\)|rgba\(\s{0,31}[\d]{1,3}\s{0,31},\s{0,31}[\d]{1,3}\s{0,31},\s{0,31}[\d]{1,3}\s{0,31},\s{0,31}[.\d]+\s{0,31}\)$/i;
// eslint-disable-next-line max-len
var rgbColorWithSpacesRegex = /^rgb\(\s{0,31}[\d]{1,3}\s{1,31}[\d]{1,3}\s{1,31}[\d]{1,3}\s{0,31}\)|rgba\(\s{0,31}[\d]{1,3}\s{1,31}[\d]{1,3}\s{1,31}[\d]{1,3}\s{1,31}\/\s{1,31}[\d]*\.?[.\d]+%?\s{0,31}\)$/i;
var timeUnitPattern = /\d+(s|ms)/;
var timingFunctionRegex = /^(cubic-bezier|steps)\([^)]+\)$/;
var validTimeUnits = ['ms', 's'];
var urlRegex = /^url\([\s\S]+\)$/i;
var variableRegex = new RegExp('^' + variableRegexStr + '$', 'i');

var eightValueColorRegex = /^#[0-9a-f]{8}$/i;
var fourValueColorRegex = /^#[0-9a-f]{4}$/i;
var sixValueColorRegex = /^#[0-9a-f]{6}$/i;
var threeValueColorRegex = /^#[0-9a-f]{3}$/i;

var DECIMAL_DOT = '.';
var MINUS_SIGN = '-';
var PLUS_SIGN = '+';

var Keywords = {
  '^': [
    'inherit',
    'initial',
    'unset'
  ],
  '*-style': [
    'auto',
    'dashed',
    'dotted',
    'double',
    'groove',
    'hidden',
    'inset',
    'none',
    'outset',
    'ridge',
    'solid'
  ],
  '*-timing-function': [
    'ease',
    'ease-in',
    'ease-in-out',
    'ease-out',
    'linear',
    'step-end',
    'step-start'
  ],
  'animation-direction': [
    'alternate',
    'alternate-reverse',
    'normal',
    'reverse'
  ],
  'animation-fill-mode': [
    'backwards',
    'both',
    'forwards',
    'none'
  ],
  'animation-iteration-count': [
    'infinite'
  ],
  'animation-name': [
    'none'
  ],
  'animation-play-state': [
    'paused',
    'running'
  ],
  'background-attachment': [
    'fixed',
    'inherit',
    'local',
    'scroll'
  ],
  'background-clip': [
    'border-box',
    'content-box',
    'inherit',
    'padding-box',
    'text'
  ],
  'background-origin': [
    'border-box',
    'content-box',
    'inherit',
    'padding-box'
  ],
  'background-position': [
    'bottom',
    'center',
    'left',
    'right',
    'top'
  ],
  'background-repeat': [
    'no-repeat',
    'inherit',
    'repeat',
    'repeat-x',
    'repeat-y',
    'round',
    'space'
  ],
  'background-size': [
    'auto',
    'cover',
    'contain'
  ],
  'border-collapse': [
    'collapse',
    'inherit',
    'separate'
  ],
  bottom: [
    'auto'
  ],
  clear: [
    'both',
    'left',
    'none',
    'right'
  ],
  color: [
    'transparent'
  ],
  cursor: [
    'all-scroll',
    'auto',
    'col-resize',
    'crosshair',
    'default',
    'e-resize',
    'help',
    'move',
    'n-resize',
    'ne-resize',
    'no-drop',
    'not-allowed',
    'nw-resize',
    'pointer',
    'progress',
    'row-resize',
    's-resize',
    'se-resize',
    'sw-resize',
    'text',
    'vertical-text',
    'w-resize',
    'wait'
  ],
  display: [
    'block',
    'inline',
    'inline-block',
    'inline-table',
    'list-item',
    'none',
    'table',
    'table-caption',
    'table-cell',
    'table-column',
    'table-column-group',
    'table-footer-group',
    'table-header-group',
    'table-row',
    'table-row-group'
  ],
  float: [
    'left',
    'none',
    'right'
  ],
  left: [
    'auto'
  ],
  font: [
    'caption',
    'icon',
    'menu',
    'message-box',
    'small-caption',
    'status-bar',
    'unset'
  ],
  'font-size': [
    'large',
    'larger',
    'medium',
    'small',
    'smaller',
    'x-large',
    'x-small',
    'xx-large',
    'xx-small'
  ],
  'font-stretch': [
    'condensed',
    'expanded',
    'extra-condensed',
    'extra-expanded',
    'normal',
    'semi-condensed',
    'semi-expanded',
    'ultra-condensed',
    'ultra-expanded'
  ],
  'font-style': [
    'italic',
    'normal',
    'oblique'
  ],
  'font-variant': [
    'normal',
    'small-caps'
  ],
  'font-weight': [
    '100',
    '200',
    '300',
    '400',
    '500',
    '600',
    '700',
    '800',
    '900',
    'bold',
    'bolder',
    'lighter',
    'normal'
  ],
  'line-height': [
    'normal'
  ],
  'list-style-position': [
    'inside',
    'outside'
  ],
  'list-style-type': [
    'armenian',
    'circle',
    'decimal',
    'decimal-leading-zero',
    'disc',
    'decimal|disc', // this is the default value of list-style-type, see comment in configuration.js
    'georgian',
    'lower-alpha',
    'lower-greek',
    'lower-latin',
    'lower-roman',
    'none',
    'square',
    'upper-alpha',
    'upper-latin',
    'upper-roman'
  ],
  overflow: [
    'auto',
    'hidden',
    'scroll',
    'visible'
  ],
  position: [
    'absolute',
    'fixed',
    'relative',
    'static'
  ],
  right: [
    'auto'
  ],
  'text-align': [
    'center',
    'justify',
    'left',
    'left|right', // this is the default value of list-style-type, see comment in configuration.js
    'right'
  ],
  'text-decoration': [
    'line-through',
    'none',
    'overline',
    'underline'
  ],
  'text-overflow': [
    'clip',
    'ellipsis'
  ],
  top: [
    'auto'
  ],
  'vertical-align': [
    'baseline',
    'bottom',
    'middle',
    'sub',
    'super',
    'text-bottom',
    'text-top',
    'top'
  ],
  visibility: [
    'collapse',
    'hidden',
    'visible'
  ],
  'white-space': [
    'normal',
    'nowrap',
    'pre'
  ],
  width: [
    'inherit',
    'initial',
    'medium',
    'thick',
    'thin'
  ]
};

var Units = [
  '%',
  'ch',
  'cm',
  'em',
  'ex',
  'in',
  'mm',
  'pc',
  'pt',
  'px',
  'rem',
  'vh',
  'vm',
  'vmax',
  'vmin',
  'vw'
];

function isColor(value) {
  return value != 'auto'
    && (
      isKeyword('color')(value)
      || isHexColor(value)
      || isColorFunction(value)
      || isNamedEntity(value)
    );
}

function isColorFunction(value) {
  return isRgbColor(value) || isHslColor(value);
}

function isDynamicUnit(value) {
  return calcRegex.test(value);
}

function isFunction(value) {
  return functionAnyRegex.test(value);
}

function isHexColor(value) {
  return threeValueColorRegex.test(value)
    || fourValueColorRegex.test(value)
    || sixValueColorRegex.test(value)
    || eightValueColorRegex.test(value);
}

function isHslColor(value) {
  return hslColorRegex.test(value) || hslColorWithSpacesRegex.test(value);
}

function isHexAlphaColor(value) {
  return hexAlphaColorRegex.test(value);
}

function isIdentifier(value) {
  return identifierRegex.test(value);
}

function isQuotedText(value) {
  return quotedTextRegex.test(value);
}

function isImage(value) {
  return value == 'none' || value == 'inherit' || isUrl(value);
}

function isKeyword(propertyName) {
  return function(value) {
    return Keywords[propertyName].indexOf(value) > -1;
  };
}

function isNamedEntity(value) {
  return namedEntityRegex.test(value);
}

function isNumber(value) {
  return scanForNumber(value) == value.length;
}

function isRgbColor(value) {
  return rgbColorRegex.test(value) || rgbColorWithSpacesRegex.test(value);
}

function isPrefixed(value) {
  return prefixRegex.test(value);
}

function isPositiveNumber(value) {
  return isNumber(value)
    && parseFloat(value) >= 0;
}

function isVariable(value) {
  return variableRegex.test(value);
}

function isTime(value) {
  var numberUpTo = scanForNumber(value);

  return numberUpTo == value.length && parseInt(value) === 0
    || numberUpTo > -1 && validTimeUnits.indexOf(value.slice(numberUpTo + 1)) > -1
    || isCalculatedTime(value);
}

function isCalculatedTime(value) {
  return isFunction(value) && timeUnitPattern.test(value);
}

function isTimingFunction() {
  var isTimingFunctionKeyword = isKeyword('*-timing-function');

  return function(value) {
    return isTimingFunctionKeyword(value) || timingFunctionRegex.test(value);
  };
}

function isUnit(validUnits, value) {
  var numberUpTo = scanForNumber(value);

  return numberUpTo == value.length && parseInt(value) === 0
    || numberUpTo > -1 && validUnits.indexOf(value.slice(numberUpTo + 1).toLowerCase()) > -1
    || value == 'auto'
    || value == 'inherit';
}

function isUrl(value) {
  return urlRegex.test(value);
}

function isZIndex(value) {
  return value == 'auto'
    || isNumber(value)
    || isKeyword('^')(value);
}

function scanForNumber(value) {
  var hasDot = false;
  var hasSign = false;
  var character;
  var i, l;

  for (i = 0, l = value.length; i < l; i++) {
    character = value[i];

    if (i === 0 && (character == PLUS_SIGN || character == MINUS_SIGN)) {
      hasSign = true;
    } else if (i > 0 && hasSign && (character == PLUS_SIGN || character == MINUS_SIGN)) {
      return i - 1;
    } else if (character == DECIMAL_DOT && !hasDot) {
      hasDot = true;
    } else if (character == DECIMAL_DOT && hasDot) {
      return i - 1;
    } else if (decimalRegex.test(character)) {
      continue;
    } else {
      return i - 1;
    }
  }

  return i;
}

function validator(compatibility) {
  var validUnits = Units.slice(0).filter(function(value) {
    return !(value in compatibility.units) || compatibility.units[value] === true;
  });

  if (compatibility.customUnits.rpx) {
    validUnits.push('rpx');
  }

  return {
    colorOpacity: compatibility.colors.opacity,
    colorHexAlpha: compatibility.colors.hexAlpha,
    isAnimationDirectionKeyword: isKeyword('animation-direction'),
    isAnimationFillModeKeyword: isKeyword('animation-fill-mode'),
    isAnimationIterationCountKeyword: isKeyword('animation-iteration-count'),
    isAnimationNameKeyword: isKeyword('animation-name'),
    isAnimationPlayStateKeyword: isKeyword('animation-play-state'),
    isTimingFunction: isTimingFunction(),
    isBackgroundAttachmentKeyword: isKeyword('background-attachment'),
    isBackgroundClipKeyword: isKeyword('background-clip'),
    isBackgroundOriginKeyword: isKeyword('background-origin'),
    isBackgroundPositionKeyword: isKeyword('background-position'),
    isBackgroundRepeatKeyword: isKeyword('background-repeat'),
    isBackgroundSizeKeyword: isKeyword('background-size'),
    isColor: isColor,
    isColorFunction: isColorFunction,
    isDynamicUnit: isDynamicUnit,
    isFontKeyword: isKeyword('font'),
    isFontSizeKeyword: isKeyword('font-size'),
    isFontStretchKeyword: isKeyword('font-stretch'),
    isFontStyleKeyword: isKeyword('font-style'),
    isFontVariantKeyword: isKeyword('font-variant'),
    isFontWeightKeyword: isKeyword('font-weight'),
    isFunction: isFunction,
    isGlobal: isKeyword('^'),
    isHexAlphaColor: isHexAlphaColor,
    isHslColor: isHslColor,
    isIdentifier: isIdentifier,
    isImage: isImage,
    isKeyword: isKeyword,
    isLineHeightKeyword: isKeyword('line-height'),
    isListStylePositionKeyword: isKeyword('list-style-position'),
    isListStyleTypeKeyword: isKeyword('list-style-type'),
    isNumber: isNumber,
    isPrefixed: isPrefixed,
    isPositiveNumber: isPositiveNumber,
    isQuotedText: isQuotedText,
    isRgbColor: isRgbColor,
    isStyleKeyword: isKeyword('*-style'),
    isTime: isTime,
    isUnit: isUnit.bind(null, validUnits),
    isUrl: isUrl,
    isVariable: isVariable,
    isWidth: isKeyword('width'),
    isZIndex: isZIndex
  };
}

module.exports = validator;