'use strict';
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exports.type = 'full';
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exports.active = true;
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exports.description = 'minifies styles and removes unused styles based on usage data';
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exports.params = {
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// ... CSSO options goes here
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// additional
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usage: {
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force: false, // force to use usage data even if it unsafe (document contains <script> or on* attributes)
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ids: true,
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classes: true,
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tags: true
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}
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};
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var csso = require('csso');
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/**
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* Minifies styles (<style> element + style attribute) using CSSO
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*
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* @author strarsis <strarsis@gmail.com>
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*/
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exports.fn = function(ast, options) {
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options = options || {};
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var minifyOptionsForStylesheet = cloneObject(options);
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var minifyOptionsForAttribute = cloneObject(options);
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var elems = findStyleElems(ast);
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minifyOptionsForStylesheet.usage = collectUsageData(ast, options);
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minifyOptionsForAttribute.usage = null;
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elems.forEach(function(elem) {
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if (elem.isElem('style')) {
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// <style> element
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var styleCss = elem.content[0].text || elem.content[0].cdata || [];
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var DATA = styleCss.indexOf('>') >= 0 || styleCss.indexOf('<') >= 0 ? 'cdata' : 'text';
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elem.content[0][DATA] = csso.minify(styleCss, minifyOptionsForStylesheet).css;
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} else {
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// style attribute
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var elemStyle = elem.attr('style').value;
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elem.attr('style').value = csso.minifyBlock(elemStyle, minifyOptionsForAttribute).css;
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}
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});
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return ast;
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};
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function cloneObject(obj) {
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var result = {};
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for (var key in obj) {
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result[key] = obj[key];
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}
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return result;
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}
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function findStyleElems(ast) {
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function walk(items, styles) {
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for (var i = 0; i < items.content.length; i++) {
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var item = items.content[i];
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// go deeper
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if (item.content) {
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walk(item, styles);
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}
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if (item.isElem('style') && !item.isEmpty()) {
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styles.push(item);
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} else if (item.isElem() && item.hasAttr('style')) {
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styles.push(item);
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}
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}
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return styles;
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}
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return walk(ast, []);
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}
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function shouldFilter(options, name) {
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if ('usage' in options === false) {
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return true;
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}
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if (options.usage && name in options.usage === false) {
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return true;
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}
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return Boolean(options.usage && options.usage[name]);
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}
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function collectUsageData(ast, options) {
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function walk(items, usageData) {
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for (var i = 0; i < items.content.length; i++) {
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var item = items.content[i];
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// go deeper
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if (item.content) {
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walk(item, usageData);
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}
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if (item.isElem('script')) {
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safe = false;
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}
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if (item.isElem()) {
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usageData.tags[item.elem] = true;
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if (item.hasAttr('id')) {
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usageData.ids[item.attr('id').value] = true;
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}
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if (item.hasAttr('class')) {
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item.attr('class').value.replace(/^\s+|\s+$/g, '').split(/\s+/).forEach(function(className) {
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usageData.classes[className] = true;
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});
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}
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if (item.attrs && Object.keys(item.attrs).some(function(name) { return /^on/i.test(name); })) {
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safe = false;
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}
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}
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}
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return usageData;
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}
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var safe = true;
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var usageData = {};
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var hasData = false;
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var rawData = walk(ast, {
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ids: Object.create(null),
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classes: Object.create(null),
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tags: Object.create(null)
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});
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if (!safe && options.usage && options.usage.force) {
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safe = true;
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}
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for (var key in rawData) {
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if (shouldFilter(options, key)) {
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usageData[key] = Object.keys(rawData[key]);
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hasData = true;
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}
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}
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return safe && hasData ? usageData : null;
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}
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