lepu-test-platform-web/node_modules/csso/lib/compressor/restructure/7-mergeRuleset.js

88 lines
2.6 KiB
JavaScript

var utils = require('./utils.js');
var walkRules = require('../../utils/walk.js').rules;
/*
At this step all rules has single simple selector. We try to join by equal
declaration blocks to first rule, e.g.
.a { color: red }
b { ... }
.b { color: red }
->
.a, .b { color: red }
b { ... }
*/
function processRuleset(node, item, list) {
var selectors = node.selector.selectors;
var declarations = node.block.declarations;
var nodeCompareMarker = selectors.first().compareMarker;
var skippedCompareMarkers = {};
list.nextUntil(item.next, function(next, nextItem) {
// skip non-ruleset node if safe
if (next.type !== 'Ruleset') {
return utils.unsafeToSkipNode.call(selectors, next);
}
if (node.pseudoSignature !== next.pseudoSignature) {
return true;
}
var nextFirstSelector = next.selector.selectors.head;
var nextDeclarations = next.block.declarations;
var nextCompareMarker = nextFirstSelector.data.compareMarker;
// if next ruleset has same marked as one of skipped then stop joining
if (nextCompareMarker in skippedCompareMarkers) {
return true;
}
// try to join by selectors
if (selectors.head === selectors.tail) {
if (selectors.first().id === nextFirstSelector.data.id) {
declarations.appendList(nextDeclarations);
list.remove(nextItem);
return;
}
}
// try to join by properties
if (utils.isEqualDeclarations(declarations, nextDeclarations)) {
var nextStr = nextFirstSelector.data.id;
selectors.some(function(data, item) {
var curStr = data.id;
if (nextStr < curStr) {
selectors.insert(nextFirstSelector, item);
return true;
}
if (!item.next) {
selectors.insert(nextFirstSelector);
return true;
}
});
list.remove(nextItem);
return;
}
// go to next ruleset if current one can be skipped (has no equal specificity nor element selector)
if (nextCompareMarker === nodeCompareMarker) {
return true;
}
skippedCompareMarkers[nextCompareMarker] = true;
});
};
module.exports = function mergeRuleset(ast) {
walkRules(ast, function(node, item, list) {
if (node.type === 'Ruleset') {
processRuleset(node, item, list);
}
});
};