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rOACCT/node_modules/svgo/lib/css-tools.js
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css-tools.js
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'use strict';
var csstree = require('css-tree'),
List = csstree.List,
stable = require('stable'),
specificity = require('csso/lib/restructure/prepare/specificity');
/**
* Flatten a CSS AST to a selectors list.
*
* @param {import('css-tree').CssNode} cssAst css-tree AST to flatten
* @return {Array} selectors
*/
function flattenToSelectors(cssAst) {
var selectors = [];
csstree.walk(cssAst, {
visit: 'Rule',
enter: function (node) {
if (node.type !== 'Rule') {
return;
}
var atrule = this.atrule;
var rule = node;
node.prelude.children.each(function (selectorNode, selectorItem) {
var selector = {
item: selectorItem,
atrule: atrule,
rule: rule,
pseudos: /** @type {{item: any; list: any[]}[]} */ ([]),
};
selectorNode.children.each(function (
selectorChildNode,
selectorChildItem,
selectorChildList
) {
if (
selectorChildNode.type === 'PseudoClassSelector' ||
selectorChildNode.type === 'PseudoElementSelector'
) {
selector.pseudos.push({
item: selectorChildItem,
list: selectorChildList,
});
}
});
selectors.push(selector);
});
},
});
return selectors;
}
/**
* Filter selectors by Media Query.
*
* @param {Array} selectors to filter
* @param {Array} useMqs Array with strings of media queries that should pass (<name> <expression>)
* @return {Array} Filtered selectors that match the passed media queries
*/
function filterByMqs(selectors, useMqs) {
return selectors.filter(function (selector) {
if (selector.atrule === null) {
return ~useMqs.indexOf('');
}
var mqName = selector.atrule.name;
var mqStr = mqName;
if (
selector.atrule.expression &&
selector.atrule.expression.children.first().type === 'MediaQueryList'
) {
var mqExpr = csstree.generate(selector.atrule.expression);
mqStr = [mqName, mqExpr].join(' ');
}
return ~useMqs.indexOf(mqStr);
});
}
/**
* Filter selectors by the pseudo-elements and/or -classes they contain.
*
* @param {Array} selectors to filter
* @param {Array} usePseudos Array with strings of single or sequence of pseudo-elements and/or -classes that should pass
* @return {Array} Filtered selectors that match the passed pseudo-elements and/or -classes
*/
function filterByPseudos(selectors, usePseudos) {
return selectors.filter(function (selector) {
var pseudoSelectorsStr = csstree.generate({
type: 'Selector',
children: new List().fromArray(
selector.pseudos.map(function (pseudo) {
return pseudo.item.data;
})
),
});
return ~usePseudos.indexOf(pseudoSelectorsStr);
});
}
/**
* Remove pseudo-elements and/or -classes from the selectors for proper matching.
*
* @param {Array} selectors to clean
* @return {void}
*/
function cleanPseudos(selectors) {
selectors.forEach(function (selector) {
selector.pseudos.forEach(function (pseudo) {
pseudo.list.remove(pseudo.item);
});
});
}
/**
* Compares two selector specificities.
* extracted from https://github.com/keeganstreet/specificity/blob/master/specificity.js#L211
*
* @param {Array} aSpecificity Specificity of selector A
* @param {Array} bSpecificity Specificity of selector B
* @return {number} Score of selector specificity A compared to selector specificity B
*/
function compareSpecificity(aSpecificity, bSpecificity) {
for (var i = 0; i < 4; i += 1) {
if (aSpecificity[i] < bSpecificity[i]) {
return -1;
} else if (aSpecificity[i] > bSpecificity[i]) {
return 1;
}
}
return 0;
}
/**
* Compare two simple selectors.
*
* @param {Object} aSimpleSelectorNode Simple selector A
* @param {Object} bSimpleSelectorNode Simple selector B
* @return {number} Score of selector A compared to selector B
*/
function compareSimpleSelectorNode(aSimpleSelectorNode, bSimpleSelectorNode) {
var aSpecificity = specificity(aSimpleSelectorNode),
bSpecificity = specificity(bSimpleSelectorNode);
return compareSpecificity(aSpecificity, bSpecificity);
}
function _bySelectorSpecificity(selectorA, selectorB) {
return compareSimpleSelectorNode(selectorA.item.data, selectorB.item.data);
}
/**
* Sort selectors stably by their specificity.
*
* @param {Array} selectors to be sorted
* @return {Array} Stable sorted selectors
*/
function sortSelectors(selectors) {
return stable(selectors, _bySelectorSpecificity);
}
/**
* Convert a css-tree AST style declaration to CSSStyleDeclaration property.
*
* @param {import('css-tree').CssNode} declaration css-tree style declaration
* @return {Object} CSSStyleDeclaration property
*/
function csstreeToStyleDeclaration(declaration) {
var propertyName = declaration.property,
propertyValue = csstree.generate(declaration.value),
propertyPriority = declaration.important ? 'important' : '';
return {
name: propertyName,
value: propertyValue,
priority: propertyPriority,
};
}
/**
* Gets the CSS string of a style element
*
* @param {Object} elem style element
* @return {string} CSS string or empty array if no styles are set
*/
function getCssStr(elem) {
if (
elem.children.length > 0 &&
(elem.children[0].type === 'text' || elem.children[0].type === 'cdata')
) {
return elem.children[0].value;
}
return '';
}
/**
* Sets the CSS string of a style element
*
* @param {Object} elem style element
* @param {string} css string to be set
* @return {string} reference to field with CSS
*/
function setCssStr(elem, css) {
if (elem.children.length === 0) {
elem.children.push({
type: 'text',
value: '',
});
}
if (elem.children[0].type !== 'text' && elem.children[0].type !== 'cdata') {
return css;
}
elem.children[0].value = css;
return css;
}
module.exports.flattenToSelectors = flattenToSelectors;
module.exports.filterByMqs = filterByMqs;
module.exports.filterByPseudos = filterByPseudos;
module.exports.cleanPseudos = cleanPseudos;
module.exports.compareSpecificity = compareSpecificity;
module.exports.compareSimpleSelectorNode = compareSimpleSelectorNode;
module.exports.sortSelectors = sortSelectors;
module.exports.csstreeToStyleDeclaration = csstreeToStyleDeclaration;
module.exports.getCssStr = getCssStr;
module.exports.setCssStr = setCssStr;
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