241 lines
8.0 KiB
JavaScript
241 lines
8.0 KiB
JavaScript
'use strict';
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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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 _cssnanoUtilSameParent = require('cssnano-util-same-parent');
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var _cssnanoUtilSameParent2 = _interopRequireDefault(_cssnanoUtilSameParent);
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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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const prefixes = _vendors2.default.map(v => `-${v}-`);
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function intersect(a, b, not) {
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return a.filter(c => {
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const index = ~b.indexOf(c);
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return not ? !index : index;
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});
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}
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// Internet Explorer use :-ms-input-placeholder.
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// Microsoft Edge use ::-ms-input-placeholder.
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const findMsInputPlaceholder = selector => ~selector.search(/-ms-input-placeholder/i);
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const different = (a, b) => intersect(a, b, true).concat(intersect(b, a, true));
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const filterPrefixes = selector => intersect(prefixes, selector);
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function sameVendor(selectorsA, selectorsB) {
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let same = selectors => selectors.map(filterPrefixes).join();
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let findMsVendor = selectors => selectors.find(findMsInputPlaceholder);
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return same(selectorsA) === same(selectorsB) && !(findMsVendor(selectorsA) && findMsVendor(selectorsB));
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}
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const noVendor = selector => !filterPrefixes(selector).length;
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function canMerge(ruleA, ruleB, browsers, compatibilityCache) {
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const a = ruleA.selectors;
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const b = ruleB.selectors;
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const 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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const parent = (0, _cssnanoUtilSameParent2.default)(ruleA, ruleB);
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const { name } = ruleA.parent;
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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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const getDecls = rule => rule.nodes && rule.nodes.map(String);
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const joinSelectors = (...rules) => rules.map(s => s.selector).join();
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function ruleLength(...rules) {
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return rules.map(r => r.nodes.length ? String(r) : '').join('').length;
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}
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function splitProp(prop) {
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const parts = prop.split('-');
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let base, rest;
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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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const a = splitProp(propA);
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const 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(prop => isConflictingProp(prop, declProp));
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}
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function partialMerge(first, second) {
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let 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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let nextRule = second.next();
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if (nextRule && nextRule.type === 'rule' && canMerge(second, nextRule)) {
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let 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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const recievingBlock = second.clone();
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recievingBlock.selector = joinSelectors(first, second);
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recievingBlock.nodes = [];
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const difference = different(getDecls(first), getDecls(second));
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const filterConflicts = (decls, intersectn) => {
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let willNotMove = [];
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return decls.reduce((willMove, decl) => {
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let intersects = ~intersectn.indexOf(decl);
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let prop = decl.split(':')[0];
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let base = prop.split('-')[0];
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let canMove = difference.every(d => d.split(':')[0] !== base);
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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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const containsAllDeclaration = intersectionList => {
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return intersectionList.some(declaration => {
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return declaration.split(':')[0].toLowerCase() === 'all';
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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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// Rules with "all" declarations must be on top
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if (containsAllDeclaration(intersection)) {
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second.parent.insertBefore(first, recievingBlock);
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} else {
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second.parent.insertBefore(second, recievingBlock);
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}
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const firstClone = first.clone();
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const secondClone = second.clone();
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const moveDecl = callback => {
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return 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(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(decl => decl.remove()));
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const merged = ruleLength(firstClone, recievingBlock, secondClone);
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const 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(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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let 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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const cached = getDecls(cache);
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rule.walk(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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cache.append(decl);
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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', () => {
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return (css, result) => {
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const resultOpts = result.opts || {};
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const browsers = (0, _browserslist2.default)(null, {
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stats: resultOpts.stats,
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path: __dirname,
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env: resultOpts.env
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});
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const 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']; |