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