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var walk = require('css-tree').walk;
var utils = require('./utils');
function processRule(node, item, list) {
var selectors = node.prelude.children;
var 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);
}
var prevSelectors = prev.prelude.children;
var 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
module.exports = function initialMergeRule(ast) {
walk(ast, {
visit: 'Rule',
enter: processRule
});
};