86 lines
2.5 KiB
JavaScript
86 lines
2.5 KiB
JavaScript
var walk = require('css-tree').walk;
|
|
var utils = require('./utils');
|
|
|
|
/*
|
|
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 processRule(node, item, list) {
|
|
var selectors = node.prelude.children;
|
|
var declarations = node.block.children;
|
|
var nodeCompareMarker = selectors.first().compareMarker;
|
|
var skippedCompareMarkers = {};
|
|
|
|
list.nextUntil(item.next, function(next, nextItem) {
|
|
// skip non-ruleset node if safe
|
|
if (next.type !== 'Rule') {
|
|
return utils.unsafeToSkipNode.call(selectors, next);
|
|
}
|
|
|
|
if (node.pseudoSignature !== next.pseudoSignature) {
|
|
return true;
|
|
}
|
|
|
|
var nextFirstSelector = next.prelude.children.head;
|
|
var nextDeclarations = next.block.children;
|
|
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 mergeRule(ast) {
|
|
walk(ast, {
|
|
visit: 'Rule',
|
|
enter: processRule
|
|
});
|
|
};
|