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- 'use strict';
-
- Object.defineProperty(exports, "__esModule", {
- value: true
- });
-
- var _browserslist = require('browserslist');
-
- var _browserslist2 = _interopRequireDefault(_browserslist);
-
- var _postcss = require('postcss');
-
- var _postcss2 = _interopRequireDefault(_postcss);
-
- var _vendors = require('vendors');
-
- var _vendors2 = _interopRequireDefault(_vendors);
-
- var _cssnanoUtilSameParent = require('cssnano-util-same-parent');
-
- var _cssnanoUtilSameParent2 = _interopRequireDefault(_cssnanoUtilSameParent);
-
- var _ensureCompatibility = require('./lib/ensureCompatibility');
-
- var _ensureCompatibility2 = _interopRequireDefault(_ensureCompatibility);
-
- function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
-
- const prefixes = _vendors2.default.map(v => `-${v}-`);
-
- function intersect(a, b, not) {
- return a.filter(c => {
- const index = ~b.indexOf(c);
- return not ? !index : index;
- });
- }
-
- // Internet Explorer use :-ms-input-placeholder.
- // Microsoft Edge use ::-ms-input-placeholder.
- const findMsInputPlaceholder = selector => ~selector.search(/-ms-input-placeholder/i);
- const different = (a, b) => intersect(a, b, true).concat(intersect(b, a, true));
- const filterPrefixes = selector => intersect(prefixes, selector);
-
- function sameVendor(selectorsA, selectorsB) {
- let same = selectors => selectors.map(filterPrefixes).join();
- let findMsVendor = selectors => selectors.find(findMsInputPlaceholder);
- return same(selectorsA) === same(selectorsB) && !(findMsVendor(selectorsA) && findMsVendor(selectorsB));
- }
-
- const noVendor = selector => !filterPrefixes(selector).length;
-
- function canMerge(ruleA, ruleB, browsers, compatibilityCache) {
- const a = ruleA.selectors;
- const b = ruleB.selectors;
-
- const selectors = a.concat(b);
-
- if (!(0, _ensureCompatibility2.default)(selectors, browsers, compatibilityCache)) {
- return false;
- }
-
- const parent = (0, _cssnanoUtilSameParent2.default)(ruleA, ruleB);
- const { name } = ruleA.parent;
- if (parent && name && ~name.indexOf('keyframes')) {
- return false;
- }
- return parent && (selectors.every(noVendor) || sameVendor(a, b));
- }
-
- const getDecls = rule => rule.nodes && rule.nodes.map(String);
- const joinSelectors = (...rules) => rules.map(s => s.selector).join();
-
- function ruleLength(...rules) {
- return rules.map(r => r.nodes.length ? String(r) : '').join('').length;
- }
-
- function splitProp(prop) {
- const parts = prop.split('-');
- let base, rest;
- // Treat vendor prefixed properties as if they were unprefixed;
- // moving them when combined with non-prefixed properties can
- // cause issues. e.g. moving -webkit-background-clip when there
- // is a background shorthand definition.
- if (prop[0] === '-') {
- base = parts[2];
- rest = parts.slice(3);
- } else {
- base = parts[0];
- rest = parts.slice(1);
- }
- return [base, rest];
- }
-
- function isConflictingProp(propA, propB) {
- if (propA === propB) {
- return true;
- }
- const a = splitProp(propA);
- const b = splitProp(propB);
- return a[0] === b[0] && a[1].length !== b[1].length;
- }
-
- function hasConflicts(declProp, notMoved) {
- return notMoved.some(prop => isConflictingProp(prop, declProp));
- }
-
- function partialMerge(first, second) {
- let intersection = intersect(getDecls(first), getDecls(second));
- if (!intersection.length) {
- return second;
- }
- let nextRule = second.next();
- if (nextRule && nextRule.type === 'rule' && canMerge(second, nextRule)) {
- let nextIntersection = intersect(getDecls(second), getDecls(nextRule));
- if (nextIntersection.length > intersection.length) {
- first = second;second = nextRule;intersection = nextIntersection;
- }
- }
- const recievingBlock = second.clone();
- recievingBlock.selector = joinSelectors(first, second);
- recievingBlock.nodes = [];
- const difference = different(getDecls(first), getDecls(second));
- const filterConflicts = (decls, intersectn) => {
- let willNotMove = [];
- return decls.reduce((willMove, decl) => {
- let intersects = ~intersectn.indexOf(decl);
- let prop = decl.split(':')[0];
- let base = prop.split('-')[0];
- let canMove = difference.every(d => d.split(':')[0] !== base);
- if (intersects && canMove && !hasConflicts(prop, willNotMove)) {
- willMove.push(decl);
- } else {
- willNotMove.push(prop);
- }
- return willMove;
- }, []);
- };
- const containsAllDeclaration = intersectionList => {
- return intersectionList.some(declaration => {
- return declaration.split(':')[0].toLowerCase() === 'all';
- });
- };
- intersection = filterConflicts(getDecls(first).reverse(), intersection);
- intersection = filterConflicts(getDecls(second), intersection);
-
- // Rules with "all" declarations must be on top
- if (containsAllDeclaration(intersection)) {
- second.parent.insertBefore(first, recievingBlock);
- } else {
- second.parent.insertBefore(second, recievingBlock);
- }
-
- const firstClone = first.clone();
- const secondClone = second.clone();
- const moveDecl = callback => {
- return decl => {
- if (~intersection.indexOf(String(decl))) {
- callback.call(this, decl);
- }
- };
- };
- firstClone.walkDecls(moveDecl(decl => {
- decl.remove();
- recievingBlock.append(decl);
- }));
- secondClone.walkDecls(moveDecl(decl => decl.remove()));
- const merged = ruleLength(firstClone, recievingBlock, secondClone);
- const original = ruleLength(first, second);
- if (merged < original) {
- first.replaceWith(firstClone);
- second.replaceWith(secondClone);
- [firstClone, recievingBlock, secondClone].forEach(r => {
- if (!r.nodes.length) {
- r.remove();
- }
- });
- if (!secondClone.parent) {
- return recievingBlock;
- }
- return secondClone;
- } else {
- recievingBlock.remove();
- return second;
- }
- }
-
- function selectorMerger(browsers, compatibilityCache) {
- let cache = null;
- return function (rule) {
- // Prime the cache with the first rule, or alternately ensure that it is
- // safe to merge both declarations before continuing
- if (!cache || !canMerge(rule, cache, browsers, compatibilityCache)) {
- cache = rule;
- return;
- }
- // Ensure that we don't deduplicate the same rule; this is sometimes
- // caused by a partial merge
- if (cache === rule) {
- cache = rule;
- return;
- }
- // Merge when declarations are exactly equal
- // e.g. h1 { color: red } h2 { color: red }
- if (getDecls(rule).join(';') === getDecls(cache).join(';')) {
- rule.selector = joinSelectors(cache, rule);
- cache.remove();
- cache = rule;
- return;
- }
- // Merge when both selectors are exactly equal
- // e.g. a { color: blue } a { font-weight: bold }
- if (cache.selector === rule.selector) {
- const cached = getDecls(cache);
- rule.walk(decl => {
- if (~cached.indexOf(String(decl))) {
- return decl.remove();
- }
- cache.append(decl);
- });
- rule.remove();
- return;
- }
- // Partial merge: check if the rule contains a subset of the last; if
- // so create a joined selector with the subset, if smaller.
- cache = partialMerge(cache, rule);
- };
- }
-
- exports.default = _postcss2.default.plugin('postcss-merge-rules', () => {
- return (css, result) => {
- const resultOpts = result.opts || {};
- const browsers = (0, _browserslist2.default)(null, {
- stats: resultOpts.stats,
- path: __dirname,
- env: resultOpts.env
- });
- const compatibilityCache = {};
- css.walkRules(selectorMerger(browsers, compatibilityCache));
- };
- });
- module.exports = exports['default'];
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