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- 'use strict';
- /**
- * @param {string | undefined} value
- * @return {string | undefined}
- */
- function trimValue(value) {
- return value ? value.trim() : value;
- }
-
- /**
- * @param {{nodes: import('postcss').Node[]}} node
- * @return {boolean}
- */
- function empty(node) {
- return !node.nodes.filter((child) => child.type !== 'comment').length;
- }
-
- /**
- * @param {import('postcss').AnyNode} nodeA
- * @param {import('postcss').AnyNode} nodeB
- * @return {boolean}
- */
- function equals(nodeA, nodeB) {
- const a = /** @type {any} */ (nodeA);
- const b = /** @type {any} */ (nodeB);
- if (a.type !== b.type) {
- return false;
- }
-
- if (a.important !== b.important) {
- return false;
- }
-
- if ((a.raws && !b.raws) || (!a.raws && b.raws)) {
- return false;
- }
-
- switch (a.type) {
- case 'rule':
- if (a.selector !== b.selector) {
- return false;
- }
- break;
- case 'atrule':
- if (a.name !== b.name || a.params !== b.params) {
- return false;
- }
-
- if (a.raws && trimValue(a.raws.before) !== trimValue(b.raws.before)) {
- return false;
- }
-
- if (
- a.raws &&
- trimValue(a.raws.afterName) !== trimValue(b.raws.afterName)
- ) {
- return false;
- }
- break;
- case 'decl':
- if (a.prop !== b.prop || a.value !== b.value) {
- return false;
- }
-
- if (a.raws && trimValue(a.raws.before) !== trimValue(b.raws.before)) {
- return false;
- }
- break;
- }
-
- if (a.nodes) {
- if (a.nodes.length !== b.nodes.length) {
- return false;
- }
-
- for (let i = 0; i < a.nodes.length; i++) {
- if (!equals(a.nodes[i], b.nodes[i])) {
- return false;
- }
- }
- }
- return true;
- }
-
- /**
- * @param {import('postcss').Rule} last
- * @param {import('postcss').AnyNode[]} nodes
- * @return {void}
- */
- function dedupeRule(last, nodes) {
- let index = nodes.indexOf(last) - 1;
- while (index >= 0) {
- const node = nodes[index--];
- if (node && node.type === 'rule' && node.selector === last.selector) {
- last.each((child) => {
- if (child.type === 'decl') {
- dedupeNode(child, node.nodes);
- }
- });
-
- if (empty(node)) {
- node.remove();
- }
- }
- }
- }
-
- /**
- * @param {import('postcss').AtRule | import('postcss').Declaration} last
- * @param {import('postcss').AnyNode[]} nodes
- * @return {void}
- */
- function dedupeNode(last, nodes) {
- let index = nodes.includes(last) ? nodes.indexOf(last) - 1 : nodes.length - 1;
-
- while (index >= 0) {
- const node = nodes[index--];
- if (node && equals(node, last)) {
- node.remove();
- }
- }
- }
-
- /**
- * @param {import('postcss').AnyNode} root
- * @return {void}
- */
- function dedupe(root) {
- const { nodes } =
- /** @type {import('postcss').Container<import('postcss').ChildNode>} */ (
- root
- );
-
- if (!nodes) {
- return;
- }
-
- let index = nodes.length - 1;
- while (index >= 0) {
- let last = nodes[index--];
- if (!last || !last.parent) {
- continue;
- }
- dedupe(last);
- if (last.type === 'rule') {
- dedupeRule(last, nodes);
- } else if (last.type === 'atrule' || last.type === 'decl') {
- dedupeNode(last, nodes);
- }
- }
- }
-
- /**
- * @type {import('postcss').PluginCreator<void>}
- * @return {import('postcss').Plugin}
- */
- function pluginCreator() {
- return {
- postcssPlugin: 'postcss-discard-duplicates',
- OnceExit(css) {
- dedupe(css);
- },
- };
- }
-
- pluginCreator.postcss = true;
- module.exports = pluginCreator;
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