var DEFAULTS = { '*': { colors: { hexAlpha: false, // 4- and 8-character hex notation opacity: true // rgba / hsla }, customUnits: { rpx: false }, properties: { backgroundClipMerging: true, // background-clip to shorthand backgroundOriginMerging: true, // background-origin to shorthand backgroundSizeMerging: true, // background-size to shorthand colors: true, // any kind of color transformations, like `#ff00ff` to `#f0f` or `#fff` into `red` ieBangHack: false, // !ie suffix hacks on IE<8 ieFilters: false, // whether to preserve `filter` and `-ms-filter` properties iePrefixHack: false, // underscore / asterisk prefix hacks on IE ieSuffixHack: false, // \9 suffix hacks on IE6-9, \0 suffix hack on IE6-11 merging: true, // merging properties into one shorterLengthUnits: false, // optimize pixel units into `pt`, `pc` or `in` units spaceAfterClosingBrace: true, // 'url() no-repeat' to 'url()no-repeat' urlQuotes: true, // whether to wrap content of `url()` into quotes or not zeroUnits: true // 0[unit] -> 0 }, selectors: { adjacentSpace: false, // div+ nav Android stock browser hack ie7Hack: false, // *+html hack mergeablePseudoClasses: [ ':active', ':after', ':before', ':empty', ':checked', ':disabled', ':empty', ':enabled', ':first-child', ':first-letter', ':first-line', ':first-of-type', ':focus', ':hover', ':lang', ':last-child', ':last-of-type', ':link', ':not', ':nth-child', ':nth-last-child', ':nth-last-of-type', ':nth-of-type', ':only-child', ':only-of-type', ':root', ':target', ':visited' ], // selectors with these pseudo-classes can be merged as these are universally supported mergeablePseudoElements: [ '::after', '::before', '::first-letter', '::first-line' ], // selectors with these pseudo-elements can be merged as these are universally supported mergeLimit: 8191, // number of rules that can be safely merged together multiplePseudoMerging: true }, units: { ch: true, in: true, pc: true, pt: true, rem: true, vh: true, vm: true, // vm is vmin on IE9+ see https://developer.mozilla.org/en-US/docs/Web/CSS/length vmax: true, vmin: true, vw: true } } }; DEFAULTS.ie11 = merge(DEFAULTS['*'], { properties: { ieSuffixHack: true } }); DEFAULTS.ie10 = merge(DEFAULTS['*'], { properties: { ieSuffixHack: true } }); DEFAULTS.ie9 = merge(DEFAULTS['*'], { properties: { ieFilters: true, ieSuffixHack: true } }); DEFAULTS.ie8 = merge(DEFAULTS.ie9, { colors: { opacity: false }, properties: { backgroundClipMerging: false, backgroundOriginMerging: false, backgroundSizeMerging: false, iePrefixHack: true, merging: false }, selectors: { mergeablePseudoClasses: [ ':after', ':before', ':first-child', ':first-letter', ':focus', ':hover', ':visited' ], mergeablePseudoElements: [] }, units: { ch: false, rem: false, vh: false, vm: false, vmax: false, vmin: false, vw: false } }); DEFAULTS.ie7 = merge(DEFAULTS.ie8, { properties: { ieBangHack: true }, selectors: { ie7Hack: true, mergeablePseudoClasses: [ ':first-child', ':first-letter', ':hover', ':visited' ] } }); function compatibilityFrom(source) { return merge(DEFAULTS['*'], calculateSource(source)); } function merge(source, target) { for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { var value = source[key]; if (Object.prototype.hasOwnProperty.call(target, key) && typeof value === 'object' && !Array.isArray(value)) { target[key] = merge(value, target[key] || {}); } else { target[key] = key in target ? target[key] : value; } } } return target; } function calculateSource(source) { if (typeof source == 'object') { return source; } if (!/[,+-]/.test(source)) { return DEFAULTS[source] || DEFAULTS['*']; } var parts = source.split(','); var template = parts[0] in DEFAULTS ? DEFAULTS[parts.shift()] : DEFAULTS['*']; source = {}; parts.forEach(function(part) { var isAdd = part[0] == '+'; var key = part.substring(1).split('.'); var group = key[0]; var option = key[1]; source[group] = source[group] || {}; source[group][option] = isAdd; }); return merge(template, source); } module.exports = compatibilityFrom;