62 lines
1.7 KiB
JavaScript
62 lines
1.7 KiB
JavaScript
'use strict';
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const { isRoot, isAtRule, isRule } = require('./typeGuards');
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/** @typedef {import('postcss').Root} Root */
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/** @typedef {import('postcss').Root} Document */
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/** @typedef {import('postcss').Node} PostcssNode */
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/** @typedef {import('postcss').Container} PostcssContainerNode */
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/** @typedef {import('postcss').Declaration} Declaration */
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/** @typedef {(callbackFn: (decl: Declaration, index: number, decls: Declaration[]) => void) => void} EachDeclaration */
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/**
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* @param {PostcssNode} node
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* @returns {node is PostcssContainerNode}
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*/
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function isContainerNode(node) {
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return isRule(node) || isAtRule(node) || isRoot(node);
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}
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/**
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* In order to accommodate nested blocks (postcss-nested),
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* we need to run a shallow loop (instead of eachDecl() or eachRule(),
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* which loop recursively) and allow each nested block to accumulate
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* its own list of properties -- so that a property in a nested rule
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* does not conflict with the same property in the parent rule
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* executes a provided function once for each declaration block.
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*
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* @param {Root | Document} root - root element of file.
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* @param {(eachDecl: EachDeclaration) => void} callback - Function to execute for each declaration block
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*
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* @returns {void}
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*/
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module.exports = function eachDeclarationBlock(root, callback) {
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/**
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* @param {PostcssNode} statement
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*
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* @returns {void}
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*/
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function each(statement) {
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if (!isContainerNode(statement)) return;
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if (statement.nodes && statement.nodes.length) {
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/** @type {Declaration[]} */
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const decls = [];
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for (const node of statement.nodes) {
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if (node.type === 'decl') {
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decls.push(node);
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}
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each(node);
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}
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if (decls.length) {
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callback(decls.forEach.bind(decls));
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}
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}
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}
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each(root);
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};
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