scancss/dist/handlers/handleSelector/index.js

A robust CSS stylesheet statistics collector and analyzer

'use strict';

Object.defineProperty(exports, "__esModule", {
	value: true
});
exports.handleSelector = handleSelector;

var _postcssSelectorParser = require('postcss-selector-parser');

var _postcssSelectorParser2 = _interopRequireDefault(_postcssSelectorParser);

var _cssPseudoClasses = require('../../constants/cssPseudoClasses');

var _cssPseudoElements = require('../../constants/cssPseudoElements');

var _rePrefixedString = require('../../constants/rePrefixedString');

var _reLeadingColons = require('../../constants/reLeadingColons');

var _calculateSpecificity = require('../../calculators/calculateSpecificity');

var _compareSpecificities = require('../../calculators/compareSpecificities');

var _countUsage = require('../../calculators/countUsage');

var _mergeSpecificities = require('../../converters/mergeSpecificities');

var _handleVendorPrefix = require('../handleVendorPrefix');

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

let processedSelectors = null;
function selectorsProcessor(selectors) {
	processedSelectors = selectors;
}

const selectorParser = (0, _postcssSelectorParser2.default)(selectorsProcessor);

function handlePseudoSelector(selectorObj, report) {
	const pseudoName = selectorObj.value.replace(_reLeadingColons.reLeadingColons, '');

	if (_rePrefixedString.rePrefixedString.test(pseudoName)) {
		(0, _handleVendorPrefix.handleVendorPrefix)(pseudoName, report);
	}

	if (_cssPseudoElements.cssPseudoElements.some(name => pseudoName === name)) {
		(0, _countUsage.countUsage)('pseudoElement', report.selectors.baseUsage);
		(0, _countUsage.countUsage)(selectorObj.value.replace(_reLeadingColons.reLeadingColons, '::'), report.selectors.pseudoElementsUsage);
	} else if (_cssPseudoClasses.cssPseudoClasses.some(name => pseudoName === name)) {
		(0, _countUsage.countUsage)('pseudoClass', report.selectors.baseUsage);
		(0, _countUsage.countUsage)(selectorObj.value.replace(_reLeadingColons.reLeadingColons, ':'), report.selectors.pseudoClassesUsage);
	}
}

const combinatorsMap = {
	'+': 'adjacentSibling',
	'>': 'child',
	' ': 'descendant',
	'~': 'generalSibling'
};

function isAllowedSelectorType(type) {
	return ['attribute', 'class', 'id', 'pseudo', 'tag', 'universal'].includes(type);
}

function countSelectors(selectors, report, options) {
	let tmpSpecificity = [0, 0, 0];
	let baseSelectorsWithoutCombinators = 0;

	selectors.walk(selector => {
		if (selector.type === 'combinator') {
			report.selectors.combinators.total++;
			report.selectors.combinators[combinatorsMap[selector.value]]++;
		}

		if (isAllowedSelectorType(selector.type)) {
			baseSelectorsWithoutCombinators++;

			if (selector.type === 'pseudo') {
				handlePseudoSelector(selector, report);
			} else {
				(0, _countUsage.countUsage)(selector.type, report.selectors.baseUsage);

				if (selector.type === 'attribute' && options.attributesUsage) {
					(0, _countUsage.countUsage)(String(selector), report.selectors.attributesUsage);
				}
			}

			const specificity = (0, _calculateSpecificity.calculateSpecificity)(selector);

			tmpSpecificity = (0, _mergeSpecificities.mergeSpecificities)(tmpSpecificity, specificity);
			report.selectors.specificity.total = (0, _mergeSpecificities.mergeSpecificities)(report.selectors.specificity.total, specificity);
		}
	});

	if (options.specificityGraph) {
		report.selectors.specificity.graphData.push(tmpSpecificity);
	}

	report.selectors.specificity.highest10.push({
		selector: String(selectors),
		specificity: tmpSpecificity
	});

	report.selectors.specificity.highest10 = report.selectors.specificity.highest10.sort((a, b) => (0, _compareSpecificities.compareSpecificities)(a.specificity, b.specificity));

	if (report.selectors.specificity.highest10.length > 10) {
		report.selectors.specificity.highest10.pop();
	}

	if (baseSelectorsWithoutCombinators > options.selectorComplexityThreshold) {
		report.selectors.complex++;
	}
}

function handleSelector(selector, report, options) {
	report.selectors.total++;

	(0, _countUsage.countUsage)(selector, report.selectors.usage);

	const selectorByteLength = Buffer.byteLength(selector, 'utf8');
	report.selectors.length.total += selectorByteLength;

	if (report.selectors.length.longest < selectorByteLength) {
		report.selectors.length.longest = selectorByteLength;
		report.selectors.length.longestSelector = selector;
	}

	selectorParser.processSync(selector);

	/* istanbul ignore else */
	if (processedSelectors !== null) {
		countSelectors(processedSelectors, report, options);
	}
}