var hasOwnProperty = Object.prototype.hasOwnProperty; function isEqualSelectors(a, b) { var cursor1 = a.head; var cursor2 = b.head; while (cursor1 !== null && cursor2 !== null && cursor1.data.id === cursor2.data.id) { cursor1 = cursor1.next; cursor2 = cursor2.next; } return cursor1 === null && cursor2 === null; } function isEqualDeclarations(a, b) { var cursor1 = a.head; var cursor2 = b.head; while (cursor1 !== null && cursor2 !== null && cursor1.data.id === cursor2.data.id) { cursor1 = cursor1.next; cursor2 = cursor2.next; } return cursor1 === null && cursor2 === null; } function compareDeclarations(declarations1, declarations2) { var result = { eq: [], ne1: [], ne2: [], ne2overrided: [] }; var fingerprints = Object.create(null); var declarations2hash = Object.create(null); for (var cursor = declarations2.head; cursor; cursor = cursor.next) { declarations2hash[cursor.data.id] = true; } for (var cursor = declarations1.head; cursor; cursor = cursor.next) { var data = cursor.data; if (data.fingerprint) { fingerprints[data.fingerprint] = data.important; } if (declarations2hash[data.id]) { declarations2hash[data.id] = false; result.eq.push(data); } else { result.ne1.push(data); } } for (var cursor = declarations2.head; cursor; cursor = cursor.next) { var data = cursor.data; if (declarations2hash[data.id]) { // if declarations1 has overriding declaration, this is not a difference // but take in account !important - prev should be equal or greater than follow if (hasOwnProperty.call(fingerprints, data.fingerprint) && Number(fingerprints[data.fingerprint]) >= Number(data.important)) { result.ne2overrided.push(data); } else { result.ne2.push(data); } } } return result; } function addSelectors(dest, source) { source.each(function(sourceData) { var newStr = sourceData.id; var cursor = dest.head; while (cursor) { var nextStr = cursor.data.id; if (nextStr === newStr) { return; } if (nextStr > newStr) { break; } cursor = cursor.next; } dest.insert(dest.createItem(sourceData), cursor); }); return dest; } // check if simpleselectors has no equal specificity and element selector function hasSimilarSelectors(selectors1, selectors2) { var cursor1 = selectors1.head; while (cursor1 !== null) { var cursor2 = selectors2.head; while (cursor2 !== null) { if (cursor1.data.compareMarker === cursor2.data.compareMarker) { return true; } cursor2 = cursor2.next; } cursor1 = cursor1.next; } return false; } // test node can't to be skipped function unsafeToSkipNode(node) { switch (node.type) { case 'Rule': // unsafe skip ruleset with selector similarities return hasSimilarSelectors(node.prelude.children, this); case 'Atrule': // can skip at-rules with blocks if (node.block) { // unsafe skip at-rule if block contains something unsafe to skip return node.block.children.some(unsafeToSkipNode, this); } break; case 'Declaration': return false; } // unsafe by default return true; } module.exports = { isEqualSelectors: isEqualSelectors, isEqualDeclarations: isEqualDeclarations, compareDeclarations: compareDeclarations, addSelectors: addSelectors, hasSimilarSelectors: hasSimilarSelectors, unsafeToSkipNode: unsafeToSkipNode };