270 lines
8.5 KiB
JavaScript
270 lines
8.5 KiB
JavaScript
'use strict';
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exports.__esModule = true;
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var _browserslist = require('browserslist');
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var _browserslist2 = _interopRequireDefault(_browserslist);
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var _postcss = require('postcss');
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var _postcss2 = _interopRequireDefault(_postcss);
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var _vendors = require('vendors');
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var _vendors2 = _interopRequireDefault(_vendors);
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var _clone = require('./lib/clone');
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var _clone2 = _interopRequireDefault(_clone);
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var _ensureCompatibility = require('./lib/ensureCompatibility');
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var _ensureCompatibility2 = _interopRequireDefault(_ensureCompatibility);
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function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
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var prefixes = _vendors2.default.map(function (v) {
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return '-' + v + '-';
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});
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function intersect(a, b, not) {
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return a.filter(function (c) {
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var index = ~b.indexOf(c);
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return not ? !index : index;
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});
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}
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var different = function different(a, b) {
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return intersect(a, b, true).concat(intersect(b, a, true));
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};
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var filterPrefixes = function filterPrefixes(selector) {
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return intersect(prefixes, selector);
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};
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function sameVendor(selectorsA, selectorsB) {
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var same = function same(selectors) {
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return selectors.map(filterPrefixes).join();
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};
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return same(selectorsA) === same(selectorsB);
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}
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var noVendor = function noVendor(selector) {
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return !filterPrefixes(selector).length;
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};
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function sameParent(ruleA, ruleB) {
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var hasParent = ruleA.parent && ruleB.parent;
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var sameType = hasParent && ruleA.parent.type === ruleB.parent.type;
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// If an at rule, ensure that the parameters are the same
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if (hasParent && ruleA.parent.type !== 'root' && ruleB.parent.type !== 'root') {
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sameType = sameType && ruleA.parent.params === ruleB.parent.params && ruleA.parent.name === ruleB.parent.name;
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}
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return hasParent ? sameType : true;
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}
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function canMerge(ruleA, ruleB, browsers, compatibilityCache) {
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var a = ruleA.selectors;
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var b = ruleB.selectors;
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var selectors = a.concat(b);
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if (!(0, _ensureCompatibility2.default)(selectors, browsers, compatibilityCache)) {
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return false;
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}
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var parent = sameParent(ruleA, ruleB);
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var name = ruleA.parent.name;
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if (parent && name && ~name.indexOf('keyframes')) {
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return false;
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}
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return parent && (selectors.every(noVendor) || sameVendor(a, b));
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}
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var getDecls = function getDecls(rule) {
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return rule.nodes ? rule.nodes.map(String) : [];
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};
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var joinSelectors = function joinSelectors() {
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for (var _len = arguments.length, rules = Array(_len), _key = 0; _key < _len; _key++) {
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rules[_key] = arguments[_key];
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}
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return rules.map(function (s) {
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return s.selector;
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}).join();
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};
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function ruleLength() {
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for (var _len2 = arguments.length, rules = Array(_len2), _key2 = 0; _key2 < _len2; _key2++) {
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rules[_key2] = arguments[_key2];
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}
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return rules.map(function (r) {
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return r.nodes.length ? String(r) : '';
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}).join('').length;
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}
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function splitProp(prop) {
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var parts = prop.split('-');
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var base = void 0,
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rest = void 0;
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// Treat vendor prefixed properties as if they were unprefixed;
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// moving them when combined with non-prefixed properties can
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// cause issues. e.g. moving -webkit-background-clip when there
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// is a background shorthand definition.
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if (prop[0] === '-') {
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base = parts[2];
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rest = parts.slice(3);
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} else {
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base = parts[0];
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rest = parts.slice(1);
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}
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return [base, rest];
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}
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function isConflictingProp(propA, propB) {
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if (propA === propB) {
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return true;
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}
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var a = splitProp(propA);
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var b = splitProp(propB);
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return a[0] === b[0] && a[1].length !== b[1].length;
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}
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function hasConflicts(declProp, notMoved) {
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return notMoved.some(function (prop) {
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return isConflictingProp(prop, declProp);
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});
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}
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function partialMerge(first, second) {
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var _this = this;
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var intersection = intersect(getDecls(first), getDecls(second));
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if (!intersection.length) {
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return second;
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}
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var nextRule = second.next();
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if (nextRule && nextRule.type === 'rule' && canMerge(second, nextRule)) {
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var nextIntersection = intersect(getDecls(second), getDecls(nextRule));
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if (nextIntersection.length > intersection.length) {
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first = second;second = nextRule;intersection = nextIntersection;
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}
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}
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var recievingBlock = (0, _clone2.default)(second);
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recievingBlock.selector = joinSelectors(first, second);
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recievingBlock.nodes = [];
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second.parent.insertBefore(second, recievingBlock);
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var difference = different(getDecls(first), getDecls(second));
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var filterConflicts = function filterConflicts(decls, intersectn) {
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var willNotMove = [];
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return decls.reduce(function (willMove, decl) {
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var intersects = ~intersectn.indexOf(decl);
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var prop = decl.split(':')[0];
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var base = prop.split('-')[0];
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var canMove = difference.every(function (d) {
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return d.split(':')[0] !== base;
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});
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if (intersects && canMove && !hasConflicts(prop, willNotMove)) {
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willMove.push(decl);
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} else {
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willNotMove.push(prop);
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}
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return willMove;
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}, []);
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};
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intersection = filterConflicts(getDecls(first).reverse(), intersection);
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intersection = filterConflicts(getDecls(second), intersection);
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var firstClone = (0, _clone2.default)(first);
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var secondClone = (0, _clone2.default)(second);
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var moveDecl = function moveDecl(callback) {
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return function (decl) {
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if (~intersection.indexOf(String(decl))) {
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callback.call(_this, decl);
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}
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};
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};
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firstClone.walkDecls(moveDecl(function (decl) {
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decl.remove();
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recievingBlock.append(decl);
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}));
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secondClone.walkDecls(moveDecl(function (decl) {
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return decl.remove();
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}));
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var merged = ruleLength(firstClone, recievingBlock, secondClone);
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var original = ruleLength(first, second);
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if (merged < original) {
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first.replaceWith(firstClone);
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second.replaceWith(secondClone);
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[firstClone, recievingBlock, secondClone].forEach(function (r) {
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if (!r.nodes.length) {
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r.remove();
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}
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});
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if (!secondClone.parent) {
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return recievingBlock;
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}
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return secondClone;
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} else {
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recievingBlock.remove();
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return second;
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}
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}
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function selectorMerger(browsers, compatibilityCache) {
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var cache = null;
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return function (rule) {
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// Prime the cache with the first rule, or alternately ensure that it is
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// safe to merge both declarations before continuing
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if (!cache || !canMerge(rule, cache, browsers, compatibilityCache)) {
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cache = rule;
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return;
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}
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// Ensure that we don't deduplicate the same rule; this is sometimes
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// caused by a partial merge
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if (cache === rule) {
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cache = rule;
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return;
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}
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// Merge when declarations are exactly equal
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// e.g. h1 { color: red } h2 { color: red }
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if (getDecls(rule).join(';') === getDecls(cache).join(';')) {
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rule.selector = joinSelectors(cache, rule);
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cache.remove();
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cache = rule;
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return;
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}
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// Merge when both selectors are exactly equal
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// e.g. a { color: blue } a { font-weight: bold }
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if (cache.selector === rule.selector) {
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var cached = getDecls(cache);
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rule.walk(function (decl) {
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if (~cached.indexOf(String(decl))) {
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return decl.remove();
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}
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decl.moveTo(cache);
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});
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rule.remove();
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return;
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}
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// Partial merge: check if the rule contains a subset of the last; if
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// so create a joined selector with the subset, if smaller.
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cache = partialMerge(cache, rule);
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};
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}
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exports.default = _postcss2.default.plugin('postcss-merge-rules', function () {
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return function (css, result) {
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var opts = result.opts;
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var browsers = (0, _browserslist2.default)(null, {
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stats: opts && opts.stats,
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path: opts && opts.from,
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env: opts && opts.env
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});
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var compatibilityCache = {};
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css.walkRules(selectorMerger(browsers, compatibilityCache));
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};
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});
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module.exports = exports['default']; |