var resolveProperty = require('css-tree').property; var resolveKeyword = require('css-tree').keyword; var walk = require('css-tree').walk; var generate = require('css-tree').generate; var fingerprintId = 1; var dontRestructure = { 'src': 1 // https://github.com/afelix/csso/issues/50 }; var DONT_MIX_VALUE = { // https://developer.mozilla.org/en-US/docs/Web/CSS/display#Browser_compatibility 'display': /table|ruby|flex|-(flex)?box$|grid|contents|run-in/i, // https://developer.mozilla.org/en/docs/Web/CSS/text-align 'text-align': /^(start|end|match-parent|justify-all)$/i }; var CURSOR_SAFE_VALUE = [ 'auto', 'crosshair', 'default', 'move', 'text', 'wait', 'help', 'n-resize', 'e-resize', 's-resize', 'w-resize', 'ne-resize', 'nw-resize', 'se-resize', 'sw-resize', 'pointer', 'progress', 'not-allowed', 'no-drop', 'vertical-text', 'all-scroll', 'col-resize', 'row-resize' ]; var POSITION_SAFE_VALUE = [ 'static', 'relative', 'absolute', 'fixed' ]; var NEEDLESS_TABLE = { 'border-width': ['border'], 'border-style': ['border'], 'border-color': ['border'], 'border-top': ['border'], 'border-right': ['border'], 'border-bottom': ['border'], 'border-left': ['border'], 'border-top-width': ['border-top', 'border-width', 'border'], 'border-right-width': ['border-right', 'border-width', 'border'], 'border-bottom-width': ['border-bottom', 'border-width', 'border'], 'border-left-width': ['border-left', 'border-width', 'border'], 'border-top-style': ['border-top', 'border-style', 'border'], 'border-right-style': ['border-right', 'border-style', 'border'], 'border-bottom-style': ['border-bottom', 'border-style', 'border'], 'border-left-style': ['border-left', 'border-style', 'border'], 'border-top-color': ['border-top', 'border-color', 'border'], 'border-right-color': ['border-right', 'border-color', 'border'], 'border-bottom-color': ['border-bottom', 'border-color', 'border'], 'border-left-color': ['border-left', 'border-color', 'border'], 'margin-top': ['margin'], 'margin-right': ['margin'], 'margin-bottom': ['margin'], 'margin-left': ['margin'], 'padding-top': ['padding'], 'padding-right': ['padding'], 'padding-bottom': ['padding'], 'padding-left': ['padding'], 'font-style': ['font'], 'font-variant': ['font'], 'font-weight': ['font'], 'font-size': ['font'], 'font-family': ['font'], 'list-style-type': ['list-style'], 'list-style-position': ['list-style'], 'list-style-image': ['list-style'] }; function getPropertyFingerprint(propertyName, declaration, fingerprints) { var realName = resolveProperty(propertyName).basename; if (realName === 'background') { return propertyName + ':' + generate(declaration.value); } var declarationId = declaration.id; var fingerprint = fingerprints[declarationId]; if (!fingerprint) { switch (declaration.value.type) { case 'Value': var vendorId = ''; var iehack = ''; var special = {}; var raw = false; declaration.value.children.each(function walk(node) { switch (node.type) { case 'Value': case 'Brackets': case 'Parentheses': node.children.each(walk); break; case 'Raw': raw = true; break; case 'Identifier': var name = node.name; if (!vendorId) { vendorId = resolveKeyword(name).vendor; } if (/\\[09]/.test(name)) { iehack = RegExp.lastMatch; } if (realName === 'cursor') { if (CURSOR_SAFE_VALUE.indexOf(name) === -1) { special[name] = true; } } else if (realName === 'position') { if (POSITION_SAFE_VALUE.indexOf(name) === -1) { special[name] = true; } } else if (DONT_MIX_VALUE.hasOwnProperty(realName)) { if (DONT_MIX_VALUE[realName].test(name)) { special[name] = true; } } break; case 'Function': var name = node.name; if (!vendorId) { vendorId = resolveKeyword(name).vendor; } if (name === 'rect') { // there are 2 forms of rect: // rect(, , , ) - standart // rect( ) – backwards compatible syntax // only the same form values can be merged var hasComma = node.children.some(function(node) { return node.type === 'Operator' && node.value === ','; }); if (!hasComma) { name = 'rect-backward'; } } special[name + '()'] = true; // check nested tokens too node.children.each(walk); break; case 'Dimension': var unit = node.unit; switch (unit) { // is not supported until IE11 case 'rem': // v* units is too buggy across browsers and better // don't merge values with those units case 'vw': case 'vh': case 'vmin': case 'vmax': case 'vm': // IE9 supporting "vm" instead of "vmin". special[unit] = true; break; } break; } }); fingerprint = raw ? '!' + fingerprintId++ : '!' + Object.keys(special).sort() + '|' + iehack + vendorId; break; case 'Raw': fingerprint = '!' + declaration.value.value; break; default: fingerprint = generate(declaration.value); } fingerprints[declarationId] = fingerprint; } return propertyName + fingerprint; } function needless(props, declaration, fingerprints) { var property = resolveProperty(declaration.property); if (NEEDLESS_TABLE.hasOwnProperty(property.basename)) { var table = NEEDLESS_TABLE[property.basename]; for (var i = 0; i < table.length; i++) { var ppre = getPropertyFingerprint(property.prefix + table[i], declaration, fingerprints); var prev = props.hasOwnProperty(ppre) ? props[ppre] : null; if (prev && (!declaration.important || prev.item.data.important)) { return prev; } } } } function processRule(rule, item, list, props, fingerprints) { var declarations = rule.block.children; declarations.eachRight(function(declaration, declarationItem) { var property = declaration.property; var fingerprint = getPropertyFingerprint(property, declaration, fingerprints); var prev = props[fingerprint]; if (prev && !dontRestructure.hasOwnProperty(property)) { if (declaration.important && !prev.item.data.important) { props[fingerprint] = { block: declarations, item: declarationItem }; prev.block.remove(prev.item); // TODO: use it when we can refer to several points in source // declaration.loc = { // primary: declaration.loc, // merged: prev.item.data.loc // }; } else { declarations.remove(declarationItem); // TODO: use it when we can refer to several points in source // prev.item.data.loc = { // primary: prev.item.data.loc, // merged: declaration.loc // }; } } else { var prev = needless(props, declaration, fingerprints); if (prev) { declarations.remove(declarationItem); // TODO: use it when we can refer to several points in source // prev.item.data.loc = { // primary: prev.item.data.loc, // merged: declaration.loc // }; } else { declaration.fingerprint = fingerprint; props[fingerprint] = { block: declarations, item: declarationItem }; } } }); if (declarations.isEmpty()) { list.remove(item); } } module.exports = function restructBlock(ast) { var stylesheetMap = {}; var fingerprints = Object.create(null); walk(ast, { visit: 'Rule', reverse: true, enter: function(node, item, list) { var stylesheet = this.block || this.stylesheet; var ruleId = (node.pseudoSignature || '') + '|' + node.prelude.children.first().id; var ruleMap; var props; if (!stylesheetMap.hasOwnProperty(stylesheet.id)) { ruleMap = {}; stylesheetMap[stylesheet.id] = ruleMap; } else { ruleMap = stylesheetMap[stylesheet.id]; } if (ruleMap.hasOwnProperty(ruleId)) { props = ruleMap[ruleId]; } else { props = {}; ruleMap[ruleId] = props; } processRule.call(this, node, item, list, props, fingerprints); } }); };