initial commit

node_modules/postcss-merge-rules/dist/index.js

@@ -0,0 +1,241 @@
+'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'];