2-initialMergeRuleset.cjs•1.65 kB
'use strict';
const cssTree = require('css-tree');
const utils = require('./utils.cjs');
function processRule(node, item, list) {
const selectors = node.prelude.children;
const declarations = node.block.children;
list.prevUntil(item.prev, function(prev) {
// skip non-ruleset node if safe
if (prev.type !== 'Rule') {
return utils.unsafeToSkipNode.call(selectors, prev);
}
const prevSelectors = prev.prelude.children;
const prevDeclarations = prev.block.children;
// try to join rulesets with equal pseudo signature
if (node.pseudoSignature === prev.pseudoSignature) {
// try to join by selectors
if (utils.isEqualSelectors(prevSelectors, selectors)) {
prevDeclarations.appendList(declarations);
list.remove(item);
return true;
}
// try to join by declarations
if (utils.isEqualDeclarations(declarations, prevDeclarations)) {
utils.addSelectors(prevSelectors, selectors);
list.remove(item);
return true;
}
}
// go to prev ruleset if has no selector similarities
return utils.hasSimilarSelectors(selectors, prevSelectors);
});
}
// NOTE: direction should be left to right, since rulesets merge to left
// ruleset. When direction right to left unmerged rulesets may prevent lookup
// TODO: remove initial merge
function initialMergeRule(ast) {
cssTree.walk(ast, {
visit: 'Rule',
enter: processRule
});
}
module.exports = initialMergeRule;