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backend/node_modules/postcss-merge-rules/src/index.js

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+'use strict';
+const { dirname } = require('path');
+const browserslist = require('browserslist');
+const { sameParent } = require('cssnano-utils');
+const {
+  ensureCompatibility,
+  sameVendor,
+  noVendor,
+} = require('./lib/ensureCompatibility');
+
+/**
+ * @param {import('postcss').Declaration} a
+ * @param {import('postcss').Declaration} b
+ * @return {boolean}
+ */
+function declarationIsEqual(a, b) {
+  return (
+    a.important === b.important && a.prop === b.prop && a.value === b.value
+  );
+}
+
+/**
+ * @param {import('postcss').Declaration[]} array
+ * @param {import('postcss').Declaration} decl
+ * @return {number}
+ */
+function indexOfDeclaration(array, decl) {
+  return array.findIndex((d) => declarationIsEqual(d, decl));
+}
+
+/**
+ * Returns filtered array of matched or unmatched declarations
+ * @param {import('postcss').Declaration[]} a
+ * @param {import('postcss').Declaration[]} b
+ * @param {boolean} [not=false]
+ * @return {import('postcss').Declaration[]}
+ */
+function intersect(a, b, not) {
+  return a.filter((c) => {
+    const index = indexOfDeclaration(b, c) !== -1;
+    return not ? !index : index;
+  });
+}
+
+/**
+ * @param {import('postcss').Declaration[]} a
+ * @param {import('postcss').Declaration[]} b
+ * @return {boolean}
+ */
+function sameDeclarationsAndOrder(a, b) {
+  if (a.length !== b.length) {
+    return false;
+  }
+  return a.every((d, index) => declarationIsEqual(d, b[index]));
+}
+
+/**
+ * @param {import('postcss').Rule} ruleA
+ * @param {import('postcss').Rule} ruleB
+ * @param {string[]=} browsers
+ * @param {Map<string, boolean>=} compatibilityCache
+ * @return {boolean}
+ */
+function canMerge(ruleA, ruleB, browsers, compatibilityCache) {
+  const a = ruleA.selectors;
+  const b = ruleB.selectors;
+
+  const selectors = a.concat(b);
+
+  if (!ensureCompatibility(selectors, browsers, compatibilityCache)) {
+    return false;
+  }
+
+  const parent = sameParent(
+    /** @type {any} */ (ruleA),
+    /** @type {any} */ (ruleB)
+  );
+  if (
+    parent &&
+    ruleA.parent &&
+    ruleA.parent.type === 'atrule' &&
+    /** @type {import('postcss').AtRule} */ (ruleA.parent).name.includes(
+      'keyframes'
+    )
+  ) {
+    return false;
+  }
+  if (ruleA.some(isRuleOrAtRule) || ruleB.some(isRuleOrAtRule)) {
+    return false;
+  }
+  return parent && (selectors.every(noVendor) || sameVendor(a, b));
+}
+
+/**
+ * @param {import('postcss').ChildNode} node
+ * @return {boolean}
+ */
+function isRuleOrAtRule(node) {
+  return node.type === 'rule' || node.type === 'atrule';
+}
+/**
+ * @param {import('postcss').ChildNode} node
+ * @return {node is import('postcss').Declaration}
+ */
+function isDeclaration(node) {
+  return node.type === 'decl';
+}
+/**
+ * @param {import('postcss').Rule} rule
+ * @return {import('postcss').Declaration[]}
+ */
+function getDecls(rule) {
+  return rule.nodes.filter(isDeclaration);
+}
+
+/** @type {(...rules: import('postcss').Rule[]) => string} */
+const joinSelectors = (...rules) => rules.map((s) => s.selector).join();
+
+/**
+ * @param {...import('postcss').Rule} rules
+ * @return {number}
+ */
+function ruleLength(...rules) {
+  return rules.map((r) => (r.nodes.length ? String(r) : '')).join('').length;
+}
+
+/**
+ * @param {string} prop
+ * @return {{prefix: string?, base:string?, rest:string[]}}
+ */
+function splitProp(prop) {
+  // 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.
+
+  const parts = prop.split('-');
+  if (prop[0] !== '-') {
+    return {
+      prefix: '',
+      base: parts[0],
+      rest: parts.slice(1),
+    };
+  }
+  // Don't split css variables
+  if (prop[1] === '-') {
+    return {
+      prefix: null,
+      base: null,
+      rest: [prop],
+    };
+  }
+  // Found prefix
+  return {
+    prefix: parts[1],
+    base: parts[2],
+    rest: parts.slice(3),
+  };
+}
+
+/**
+ * @param {string} propA
+ * @param {string} propB
+ * @return {boolean}
+ */
+function isConflictingProp(propA, propB) {
+  if (propA === propB) {
+    // Same specificity
+    return true;
+  }
+  const a = splitProp(propA);
+  const b = splitProp(propB);
+  // Don't resort css variables
+  if (!a.base && !b.base) {
+    return true;
+  }
+
+  // Different base and none is `place`;
+  if (a.base !== b.base && a.base !== 'place' && b.base !== 'place') {
+    return false;
+  }
+
+  // Conflict if rest-count mismatches
+  if (a.rest.length !== b.rest.length) {
+    return true;
+  }
+
+  /* Do not merge conflicting border properties */
+  if (a.base === 'border') {
+    const allRestProps = new Set([...a.rest, ...b.rest]);
+    if (
+      allRestProps.has('image') ||
+      allRestProps.has('width') ||
+      allRestProps.has('color') ||
+      allRestProps.has('style')
+    ) {
+      return true;
+    }
+  }
+  // Conflict if rest parameters are equal (same but unprefixed)
+  return a.rest.every((s, index) => b.rest[index] === s);
+}
+
+/**
+ * @param {import('postcss').Rule} first
+ * @param {import('postcss').Rule} second
+ * @return {boolean} merged
+ */
+function mergeParents(first, second) {
+  // Null check for detached rules
+  if (!first.parent || !second.parent) {
+    return false;
+  }
+
+  // Check if parents share node
+  if (first.parent === second.parent) {
+    return false;
+  }
+
+  // sameParent() already called by canMerge()
+
+  second.remove();
+  first.parent.append(second);
+  return true;
+}
+
+/**
+ * @param {import('postcss').Rule} first
+ * @param {import('postcss').Rule} second
+ * @return {import('postcss').Rule} mergedRule
+ */
+function partialMerge(first, second) {
+  let intersection = intersect(getDecls(first), getDecls(second));
+  if (intersection.length === 0) {
+    return second;
+  }
+  let nextRule = second.next();
+  if (!nextRule) {
+    // Grab next cousin
+    /** @type {any} */
+    const parentSibling =
+      /** @type {import('postcss').Container<import('postcss').ChildNode>} */ (
+        second.parent
+      ).next();
+    nextRule = parentSibling && parentSibling.nodes && parentSibling.nodes[0];
+  }
+  if (nextRule && nextRule.type === 'rule' && canMerge(second, nextRule)) {
+    let nextIntersection = intersect(getDecls(second), getDecls(nextRule));
+    if (nextIntersection.length > intersection.length) {
+      mergeParents(second, nextRule);
+      first = second;
+      second = nextRule;
+      intersection = nextIntersection;
+    }
+  }
+
+  const firstDecls = getDecls(first);
+  // Filter out intersections with later conflicts in First
+  intersection = intersection.filter((decl, intersectIndex) => {
+    const indexOfDecl = indexOfDeclaration(firstDecls, decl);
+    const nextConflictInFirst = firstDecls
+      .slice(indexOfDecl + 1)
+      .filter((d) => isConflictingProp(d.prop, decl.prop));
+    if (nextConflictInFirst.length === 0) {
+      return true;
+    }
+    const nextConflictInIntersection = intersection
+      .slice(intersectIndex + 1)
+      .filter((d) => isConflictingProp(d.prop, decl.prop));
+    if (nextConflictInFirst.length !== nextConflictInIntersection.length) {
+      return false;
+    }
+    return nextConflictInFirst.every((d, index) =>
+      declarationIsEqual(d, nextConflictInIntersection[index])
+    );
+  });
+
+  // Filter out intersections with previous conflicts in Second
+  const secondDecls = getDecls(second);
+  intersection = intersection.filter((decl) => {
+    const nextConflictIndex = secondDecls.findIndex((d) =>
+      isConflictingProp(d.prop, decl.prop)
+    );
+    if (nextConflictIndex === -1) {
+      return false;
+    }
+    if (!declarationIsEqual(secondDecls[nextConflictIndex], decl)) {
+      return false;
+    }
+    if (
+      decl.prop.toLowerCase() !== 'direction' &&
+      decl.prop.toLowerCase() !== 'unicode-bidi' &&
+      secondDecls.some(
+        (declaration) => declaration.prop.toLowerCase() === 'all'
+      )
+    ) {
+      return false;
+    }
+    secondDecls.splice(nextConflictIndex, 1);
+    return true;
+  });
+
+  if (intersection.length === 0) {
+    // Nothing to merge
+    return second;
+  }
+
+  const receivingBlock = second.clone();
+  receivingBlock.selector = joinSelectors(first, second);
+  receivingBlock.nodes = [];
+
+  /** @type {import('postcss').Container<import('postcss').ChildNode>} */ (
+    second.parent
+  ).insertBefore(second, receivingBlock);
+
+  const firstClone = first.clone();
+  const secondClone = second.clone();
+
+  /**
+   * @param {function(import('postcss').Declaration):void} callback
+   * @this void
+   * @return {function(import('postcss').Declaration)}
+   */
+  function moveDecl(callback) {
+    return (decl) => {
+      if (indexOfDeclaration(intersection, decl) !== -1) {
+        callback.call(this, decl);
+      }
+    };
+  }
+  firstClone.walkDecls(
+    moveDecl((decl) => {
+      decl.remove();
+      receivingBlock.append(decl);
+    })
+  );
+  secondClone.walkDecls(moveDecl((decl) => decl.remove()));
+  const merged = ruleLength(firstClone, receivingBlock, secondClone);
+  const original = ruleLength(first, second);
+  if (merged < original) {
+    first.replaceWith(firstClone);
+    second.replaceWith(secondClone);
+    [firstClone, receivingBlock, secondClone].forEach((r) => {
+      if (r.nodes.length === 0) {
+        r.remove();
+      }
+    });
+    if (!secondClone.parent) {
+      return receivingBlock;
+    }
+    return secondClone;
+  } else {
+    receivingBlock.remove();
+    return second;
+  }
+}
+
+/**
+ * @param {string[]} browsers
+ * @param {Map<string, boolean>} compatibilityCache
+ * @return {function(import('postcss').Rule)}
+ */
+function selectorMerger(browsers, compatibilityCache) {
+  /** @type {import('postcss').Rule | null} */
+  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;
+    }
+
+    // Parents merge: check if the rules have same parents, but not same parent nodes
+    mergeParents(cache, rule);
+
+    // Merge when declarations are exactly equal
+    // e.g. h1 { color: red } h2 { color: red }
+    if (sameDeclarationsAndOrder(getDecls(rule), getDecls(cache))) {
+      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((node) => {
+        if (node.type === 'decl' && indexOfDeclaration(cached, node) !== -1) {
+          node.remove();
+          return;
+        }
+        /** @type {import('postcss').Rule} */ (cache).append(node);
+      });
+      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);
+  };
+}
+
+/**
+ * @typedef {{ overrideBrowserslist?: string | string[] }} AutoprefixerOptions
+ * @typedef {Pick<browserslist.Options, 'stats' | 'path' | 'env'>} BrowserslistOptions
+ * @typedef {AutoprefixerOptions & BrowserslistOptions} Options
+ */
+
+/**
+ * @type {import('postcss').PluginCreator<Options>}
+ * @param {Options} opts
+ * @return {import('postcss').Plugin}
+ */
+function pluginCreator(opts = {}) {
+  return {
+    postcssPlugin: 'postcss-merge-rules',
+
+    /**
+     * @param {import('postcss').Result & {opts: BrowserslistOptions & {file?: string}}} result
+     */
+    prepare(result) {
+      const { stats, env, from, file } = result.opts || {};
+      const browsers = browserslist(opts.overrideBrowserslist, {
+        stats: opts.stats || stats,
+        path: opts.path || dirname(from || file || __filename),
+        env: opts.env || env,
+      });
+
+      const compatibilityCache = new Map();
+      return {
+        OnceExit(css) {
+          css.walkRules(selectorMerger(browsers, compatibilityCache));
+        },
+      };
+    },
+  };
+}
+
+pluginCreator.postcss = true;
+module.exports = pluginCreator;