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- function _interopDefault (ex) { return (ex && (typeof ex === 'object') && 'default' in ex) ? ex['default'] : ex; }
- var path = _interopDefault(require('path'));
- var fs = require('fs');
- var prettyBytes = _interopDefault(require('pretty-bytes'));
- var parse5 = _interopDefault(require('parse5'));
- var cssSelect = require('css-select');
- var treeAdapter = _interopDefault(require('parse5-htmlparser2-tree-adapter'));
- var postcss = require('postcss');
- var chalk = _interopDefault(require('chalk'));
- /**
- * Copyright 2018 Google LLC
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations under
- * the License.
- */
- const PARSE5_OPTS = {
- treeAdapter
- };
- /**
- * Parse HTML into a mutable, serializable DOM Document.
- * The DOM implementation is an htmlparser2 DOM enhanced with basic DOM mutation methods.
- * @param {String} html HTML to parse into a Document instance
- */
- function createDocument(html) {
- const document =
- /** @type {HTMLDocument} */
- parse5.parse(html, PARSE5_OPTS);
- defineProperties(document, DocumentExtensions); // Extend Element.prototype with DOM manipulation methods.
- const scratch = document.createElement('div'); // Get a reference to the base Node class - used by createTextNode()
- document.$$Node = scratch.constructor;
- const elementProto = Object.getPrototypeOf(scratch);
- defineProperties(elementProto, ElementExtensions);
- elementProto.ownerDocument = document;
- return document;
- }
- /**
- * Serialize a Document to an HTML String
- * @param {HTMLDocument} document A Document, such as one created via `createDocument()`
- */
- function serializeDocument(document) {
- return parse5.serialize(document, PARSE5_OPTS);
- }
- /** @typedef {treeAdapter.Document & typeof ElementExtensions} HTMLDocument */
- /**
- * Methods and descriptors to mix into Element.prototype
- * @private
- */
- const ElementExtensions = {
- /** @extends treeAdapter.Element.prototype */
- nodeName: {
- get() {
- return this.tagName.toUpperCase();
- }
- },
- id: reflectedProperty('id'),
- className: reflectedProperty('class'),
- insertBefore(child, referenceNode) {
- if (!referenceNode) return this.appendChild(child);
- treeAdapter.insertBefore(this, child, referenceNode);
- return child;
- },
- appendChild(child) {
- treeAdapter.appendChild(this, child);
- return child;
- },
- removeChild(child) {
- treeAdapter.detachNode(child);
- },
- remove() {
- treeAdapter.detachNode(this);
- },
- textContent: {
- get() {
- return getText(this);
- },
- set(text) {
- this.children = [];
- treeAdapter.insertText(this, text);
- }
- },
- setAttribute(name, value) {
- if (this.attribs == null) this.attribs = {};
- if (value == null) value = '';
- this.attribs[name] = value;
- },
- removeAttribute(name) {
- if (this.attribs != null) {
- delete this.attribs[name];
- }
- },
- getAttribute(name) {
- return this.attribs != null && this.attribs[name];
- },
- hasAttribute(name) {
- return this.attribs != null && this.attribs[name] != null;
- },
- getAttributeNode(name) {
- const value = this.getAttribute(name);
- if (value != null) return {
- specified: true,
- value
- };
- }
- };
- /**
- * Methods and descriptors to mix into the global document instance
- * @private
- */
- const DocumentExtensions = {
- /** @extends treeAdapter.Document.prototype */
- // document is just an Element in htmlparser2, giving it a nodeType of ELEMENT_NODE.
- // TODO: verify if these are needed for css-select
- nodeType: {
- get() {
- return 9;
- }
- },
- contentType: {
- get() {
- return 'text/html';
- }
- },
- nodeName: {
- get() {
- return '#document';
- }
- },
- documentElement: {
- get() {
- // Find the first <html> element within the document
- return this.childNodes.filter(child => String(child.tagName).toLowerCase() === 'html');
- }
- },
- compatMode: {
- get() {
- const compatMode = {
- 'no-quirks': 'CSS1Compat',
- quirks: 'BackCompat',
- 'limited-quirks': 'CSS1Compat'
- };
- return compatMode[treeAdapter.getDocumentMode(this)];
- }
- },
- head: {
- get() {
- return this.querySelector('head');
- }
- },
- body: {
- get() {
- return this.querySelector('body');
- }
- },
- createElement(name) {
- return treeAdapter.createElement(name, null, []);
- },
- createTextNode(text) {
- // there is no dedicated createTextNode equivalent exposed in htmlparser2's DOM
- const Node = this.$$Node;
- return new Node({
- type: 'text',
- data: text,
- parent: null,
- prev: null,
- next: null
- });
- },
- querySelector(sel) {
- return cssSelect.selectOne(sel, this.documentElement);
- },
- querySelectorAll(sel) {
- if (sel === ':root') {
- return this;
- }
- return cssSelect.selectAll(sel, this.documentElement);
- }
- };
- /**
- * Essentially `Object.defineProperties()`, except function values are assigned as value descriptors for convenience.
- * @private
- */
- function defineProperties(obj, properties) {
- for (const i in properties) {
- const value = properties[i];
- Object.defineProperty(obj, i, typeof value === 'function' ? {
- value
- } : value);
- }
- }
- /**
- * Create a property descriptor defining a getter/setter pair alias for a named attribute.
- * @private
- */
- function reflectedProperty(attributeName) {
- return {
- get() {
- return this.getAttribute(attributeName);
- },
- set(value) {
- this.setAttribute(attributeName, value);
- }
- };
- }
- /**
- * Helper to get the text content of a node
- * https://github.com/fb55/domutils/blob/master/src/stringify.ts#L21
- * @private
- */
- function getText(node) {
- if (Array.isArray(node)) return node.map(getText).join('');
- if (treeAdapter.isElementNode(node)) return node.name === 'br' ? '\n' : getText(node.children);
- if (treeAdapter.isTextNode(node)) return node.data;
- return '';
- }
- /**
- * Copyright 2018 Google LLC
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations under
- * the License.
- */
- /**
- * Parse a textual CSS Stylesheet into a Stylesheet instance.
- * Stylesheet is a mutable postcss AST with format similar to CSSOM.
- * @see https://github.com/postcss/postcss/
- * @private
- * @param {String} stylesheet
- * @returns {css.Stylesheet} ast
- */
- function parseStylesheet(stylesheet) {
- return postcss.parse(stylesheet);
- }
- /**
- * Serialize a postcss Stylesheet to a String of CSS.
- * @private
- * @param {css.Stylesheet} ast A Stylesheet to serialize, such as one returned from `parseStylesheet()`
- * @param {Object} options Options used by the stringify logic
- * @param {Boolean} [options.compress] Compress CSS output (removes comments, whitespace, etc)
- */
- function serializeStylesheet(ast, options) {
- let cssStr = '';
- postcss.stringify(ast, (result, node, type) => {
- var _node$raws;
- if (!options.compress) {
- cssStr += result;
- return;
- } // Simple minification logic
- if ((node == null ? void 0 : node.type) === 'comment') return;
- if ((node == null ? void 0 : node.type) === 'decl') {
- const prefix = node.prop + node.raws.between;
- cssStr += result.replace(prefix, prefix.trim());
- return;
- }
- if (type === 'start') {
- if (node.type === 'rule' && node.selectors) {
- cssStr += node.selectors.join(',') + '{';
- } else {
- cssStr += result.replace(/\s\{$/, '{');
- }
- return;
- }
- if (type === 'end' && result === '}' && node != null && (_node$raws = node.raws) != null && _node$raws.semicolon) {
- cssStr = cssStr.slice(0, -1);
- }
- cssStr += result.trim();
- });
- return cssStr;
- }
- /**
- * Converts a walkStyleRules() iterator to mark nodes with `.$$remove=true` instead of actually removing them.
- * This means they can be removed in a second pass, allowing the first pass to be nondestructive (eg: to preserve mirrored sheets).
- * @private
- * @param {Function} iterator Invoked on each node in the tree. Return `false` to remove that node.
- * @returns {(rule) => void} nonDestructiveIterator
- */
- function markOnly(predicate) {
- return rule => {
- const sel = rule.selectors;
- if (predicate(rule) === false) {
- rule.$$remove = true;
- }
- rule.$$markedSelectors = rule.selectors;
- if (rule._other) {
- rule._other.$$markedSelectors = rule._other.selectors;
- }
- rule.selectors = sel;
- };
- }
- /**
- * Apply filtered selectors to a rule from a previous markOnly run.
- * @private
- * @param {css.Rule} rule The Rule to apply marked selectors to (if they exist).
- */
- function applyMarkedSelectors(rule) {
- if (rule.$$markedSelectors) {
- rule.selectors = rule.$$markedSelectors;
- }
- if (rule._other) {
- applyMarkedSelectors(rule._other);
- }
- }
- /**
- * Recursively walk all rules in a stylesheet.
- * @private
- * @param {css.Rule} node A Stylesheet or Rule to descend into.
- * @param {Function} iterator Invoked on each node in the tree. Return `false` to remove that node.
- */
- function walkStyleRules(node, iterator) {
- node.nodes = node.nodes.filter(rule => {
- if (hasNestedRules(rule)) {
- walkStyleRules(rule, iterator);
- }
- rule._other = undefined;
- rule.filterSelectors = filterSelectors;
- return iterator(rule) !== false;
- });
- }
- /**
- * Recursively walk all rules in two identical stylesheets, filtering nodes into one or the other based on a predicate.
- * @private
- * @param {css.Rule} node A Stylesheet or Rule to descend into.
- * @param {css.Rule} node2 A second tree identical to `node`
- * @param {Function} iterator Invoked on each node in the tree. Return `false` to remove that node from the first tree, true to remove it from the second.
- */
- function walkStyleRulesWithReverseMirror(node, node2, iterator) {
- if (node2 === null) return walkStyleRules(node, iterator);
- [node.nodes, node2.nodes] = splitFilter(node.nodes, node2.nodes, (rule, index, rules, rules2) => {
- const rule2 = rules2[index];
- if (hasNestedRules(rule)) {
- walkStyleRulesWithReverseMirror(rule, rule2, iterator);
- }
- rule._other = rule2;
- rule.filterSelectors = filterSelectors;
- return iterator(rule) !== false;
- });
- } // Checks if a node has nested rules, like @media
- // @keyframes are an exception since they are evaluated as a whole
- function hasNestedRules(rule) {
- return rule.nodes && rule.nodes.length && rule.nodes.some(n => n.type === 'rule' || n.type === 'atrule') && rule.name !== 'keyframes' && rule.name !== '-webkit-keyframes';
- } // Like [].filter(), but applies the opposite filtering result to a second copy of the Array without a second pass.
- // This is just a quicker version of generating the compliment of the set returned from a filter operation.
- function splitFilter(a, b, predicate) {
- const aOut = [];
- const bOut = [];
- for (let index = 0; index < a.length; index++) {
- if (predicate(a[index], index, a, b)) {
- aOut.push(a[index]);
- } else {
- bOut.push(a[index]);
- }
- }
- return [aOut, bOut];
- } // can be invoked on a style rule to subset its selectors (with reverse mirroring)
- function filterSelectors(predicate) {
- if (this._other) {
- const [a, b] = splitFilter(this.selectors, this._other.selectors, predicate);
- this.selectors = a;
- this._other.selectors = b;
- } else {
- this.selectors = this.selectors.filter(predicate);
- }
- }
- const LOG_LEVELS = ['trace', 'debug', 'info', 'warn', 'error', 'silent'];
- const defaultLogger = {
- trace(msg) {
- console.trace(msg);
- },
- debug(msg) {
- console.debug(msg);
- },
- warn(msg) {
- console.warn(chalk.yellow(msg));
- },
- error(msg) {
- console.error(chalk.bold.red(msg));
- },
- info(msg) {
- console.info(chalk.bold.blue(msg));
- },
- silent() {}
- };
- function createLogger(logLevel) {
- const logLevelIdx = LOG_LEVELS.indexOf(logLevel);
- return LOG_LEVELS.reduce((logger, type, index) => {
- if (index >= logLevelIdx) {
- logger[type] = defaultLogger[type];
- } else {
- logger[type] = defaultLogger.silent;
- }
- return logger;
- }, {});
- }
- /**
- * Copyright 2018 Google LLC
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations under
- * the License.
- */
- /**
- * The mechanism to use for lazy-loading stylesheets.
- *
- * Note: <kbd>JS</kbd> indicates a strategy requiring JavaScript (falls back to `<noscript>` unless disabled).
- *
- * - **default:** Move stylesheet links to the end of the document and insert preload meta tags in their place.
- * - **"body":** Move all external stylesheet links to the end of the document.
- * - **"media":** Load stylesheets asynchronously by adding `media="not x"` and removing once loaded. <kbd>JS</kbd>
- * - **"swap":** Convert stylesheet links to preloads that swap to `rel="stylesheet"` once loaded ([details](https://www.filamentgroup.com/lab/load-css-simpler/#the-code)). <kbd>JS</kbd>
- * - **"swap-high":** Use `<link rel="alternate stylesheet preload">` and swap to `rel="stylesheet"` once loaded ([details](http://filamentgroup.github.io/loadCSS/test/new-high.html)). <kbd>JS</kbd>
- * - **"js":** Inject an asynchronous CSS loader similar to [LoadCSS](https://github.com/filamentgroup/loadCSS) and use it to load stylesheets. <kbd>JS</kbd>
- * - **"js-lazy":** Like `"js"`, but the stylesheet is disabled until fully loaded.
- * - **false:** Disables adding preload tags.
- * @typedef {(default|'body'|'media'|'swap'|'swap-high'|'js'|'js-lazy')} PreloadStrategy
- * @public
- */
- /**
- * Controls which keyframes rules are inlined.
- *
- * - **"critical":** _(default)_ inline keyframes rules that are used by the critical CSS.
- * - **"all":** Inline all keyframes rules.
- * - **"none":** Remove all keyframes rules.
- * @typedef {('critical'|'all'|'none')} KeyframeStrategy
- * @private
- * @property {String} keyframes Which {@link KeyframeStrategy keyframe strategy} to use (default: `critical`)_
- */
- /**
- * Controls log level of the plugin. Specifies the level the logger should use. A logger will
- * not produce output for any log level beneath the specified level. Available levels and order
- * are:
- *
- * - **"info"** _(default)_
- * - **"warn"**
- * - **"error"**
- * - **"trace"**
- * - **"debug"**
- * - **"silent"**
- * @typedef {('info'|'warn'|'error'|'trace'|'debug'|'silent')} LogLevel
- * @public
- */
- /**
- * Custom logger interface:
- * @typedef {object} Logger
- * @public
- * @property {function(String)} trace - Prints a trace message
- * @property {function(String)} debug - Prints a debug message
- * @property {function(String)} info - Prints an information message
- * @property {function(String)} warn - Prints a warning message
- * @property {function(String)} error - Prints an error message
- */
- /**
- * All optional. Pass them to `new Critters({ ... })`.
- * @public
- * @typedef Options
- * @property {String} path Base path location of the CSS files _(default: `''`)_
- * @property {String} publicPath Public path of the CSS resources. This prefix is removed from the href _(default: `''`)_
- * @property {Boolean} external Inline styles from external stylesheets _(default: `true`)_
- * @property {Number} inlineThreshold Inline external stylesheets smaller than a given size _(default: `0`)_
- * @property {Number} minimumExternalSize If the non-critical external stylesheet would be below this size, just inline it _(default: `0`)_
- * @property {Boolean} pruneSource Remove inlined rules from the external stylesheet _(default: `false`)_
- * @property {Boolean} mergeStylesheets Merged inlined stylesheets into a single `<style>` tag _(default: `true`)_
- * @property {String[]} additionalStylesheets Glob for matching other stylesheets to be used while looking for critical CSS.
- * @property {String} preload Which {@link PreloadStrategy preload strategy} to use
- * @property {Boolean} noscriptFallback Add `<noscript>` fallback to JS-based strategies
- * @property {Boolean} inlineFonts Inline critical font-face rules _(default: `false`)_
- * @property {Boolean} preloadFonts Preloads critical fonts _(default: `true`)_
- * @property {Boolean} fonts Shorthand for setting `inlineFonts` + `preloadFonts`
- * - Values:
- * - `true` to inline critical font-face rules and preload the fonts
- * - `false` to don't inline any font-face rules and don't preload fonts
- * @property {String} keyframes Controls which keyframes rules are inlined.
- * - Values:
- * - `"critical"`: _(default)_ inline keyframes rules used by the critical CSS
- * - `"all"` inline all keyframes rules
- * - `"none"` remove all keyframes rules
- * @property {Boolean} compress Compress resulting critical CSS _(default: `true`)_
- * @property {String} logLevel Controls {@link LogLevel log level} of the plugin _(default: `"info"`)_
- * @property {object} logger Provide a custom logger interface {@link Logger logger}
- */
- class Critters {
- /** @private */
- constructor(options) {
- this.options = Object.assign({
- logLevel: 'info',
- path: '',
- publicPath: '',
- reduceInlineStyles: true,
- pruneSource: false,
- additionalStylesheets: []
- }, options || {});
- this.urlFilter = this.options.filter;
- if (this.urlFilter instanceof RegExp) {
- this.urlFilter = this.urlFilter.test.bind(this.urlFilter);
- }
- this.logger = this.options.logger || createLogger(this.options.logLevel);
- }
- /**
- * Read the contents of a file from the specified filesystem or disk
- */
- readFile(filename) {
- const fs$1 = this.fs;
- return new Promise((resolve, reject) => {
- const callback = (err, data) => {
- if (err) reject(err);else resolve(data);
- };
- if (fs$1 && fs$1.readFile) {
- fs$1.readFile(filename, callback);
- } else {
- fs.readFile(filename, 'utf8', callback);
- }
- });
- }
- /**
- * Apply critical CSS processing to the html
- */
- async process(html) {
- const start = process.hrtime.bigint(); // Parse the generated HTML in a DOM we can mutate
- const document = createDocument(html);
- if (this.options.additionalStylesheets.length > 0) {
- this.embedAdditionalStylesheet(document);
- } // `external:false` skips processing of external sheets
- if (this.options.external !== false) {
- const externalSheets = [].slice.call(document.querySelectorAll('link[rel="stylesheet"]'));
- await Promise.all(externalSheets.map(link => this.embedLinkedStylesheet(link, document)));
- } // go through all the style tags in the document and reduce them to only critical CSS
- const styles = this.getAffectedStyleTags(document);
- await Promise.all(styles.map(style => this.processStyle(style, document)));
- if (this.options.mergeStylesheets !== false && styles.length !== 0) {
- await this.mergeStylesheets(document);
- } // serialize the document back to HTML and we're done
- const output = serializeDocument(document);
- const end = process.hrtime.bigint();
- this.logger.info('Time ' + parseFloat(end - start) / 1000000.0);
- return output;
- }
- /**
- * Get the style tags that need processing
- */
- getAffectedStyleTags(document) {
- const styles = [].slice.call(document.querySelectorAll('style')); // `inline:false` skips processing of inline stylesheets
- if (this.options.reduceInlineStyles === false) {
- return styles.filter(style => style.$$external);
- }
- return styles;
- }
- async mergeStylesheets(document) {
- const styles = this.getAffectedStyleTags(document);
- if (styles.length === 0) {
- this.logger.warn('Merging inline stylesheets into a single <style> tag skipped, no inline stylesheets to merge');
- return;
- }
- const first = styles[0];
- let sheet = first.textContent;
- for (let i = 1; i < styles.length; i++) {
- const node = styles[i];
- sheet += node.textContent;
- node.remove();
- }
- first.textContent = sheet;
- }
- /**
- * Given href, find the corresponding CSS asset
- */
- async getCssAsset(href) {
- const outputPath = this.options.path;
- const publicPath = this.options.publicPath; // CHECK - the output path
- // path on disk (with output.publicPath removed)
- let normalizedPath = href.replace(/^\//, '');
- const pathPrefix = (publicPath || '').replace(/(^\/|\/$)/g, '') + '/';
- if (normalizedPath.indexOf(pathPrefix) === 0) {
- normalizedPath = normalizedPath.substring(pathPrefix.length).replace(/^\//, '');
- } // Ignore remote stylesheets
- if (/^https?:\/\//.test(normalizedPath) || href.startsWith('//')) {
- return undefined;
- }
- const filename = path.resolve(outputPath, normalizedPath);
- let sheet;
- try {
- sheet = await this.readFile(filename);
- } catch (e) {
- this.logger.warn(`Unable to locate stylesheet: ${filename}`);
- }
- return sheet;
- }
- checkInlineThreshold(link, style, sheet) {
- if (this.options.inlineThreshold && sheet.length < this.options.inlineThreshold) {
- const href = style.$$name;
- style.$$reduce = false;
- this.logger.info(`\u001b[32mInlined all of ${href} (${sheet.length} was below the threshold of ${this.options.inlineThreshold})\u001b[39m`);
- link.remove();
- return true;
- }
- return false;
- }
- /**
- * Inline the stylesheets from options.additionalStylesheets (assuming it passes `options.filter`)
- */
- async embedAdditionalStylesheet(document) {
- const styleSheetsIncluded = [];
- const sources = await Promise.all(this.options.additionalStylesheets.map(cssFile => {
- if (styleSheetsIncluded.includes(cssFile)) {
- return;
- }
- styleSheetsIncluded.push(cssFile);
- const style = document.createElement('style');
- style.$$external = true;
- return this.getCssAsset(cssFile, style).then(sheet => [sheet, style]);
- }));
- sources.forEach(([sheet, style]) => {
- if (!sheet) return;
- style.textContent = sheet;
- document.head.appendChild(style);
- });
- }
- /**
- * Inline the target stylesheet referred to by a <link rel="stylesheet"> (assuming it passes `options.filter`)
- */
- async embedLinkedStylesheet(link, document) {
- const href = link.getAttribute('href');
- const media = link.getAttribute('media');
- const preloadMode = this.options.preload; // skip filtered resources, or network resources if no filter is provided
- if (this.urlFilter ? this.urlFilter(href) : !(href || '').match(/\.css$/)) {
- return Promise.resolve();
- } // the reduced critical CSS gets injected into a new <style> tag
- const style = document.createElement('style');
- style.$$external = true;
- const sheet = await this.getCssAsset(href, style);
- if (!sheet) {
- return;
- }
- style.textContent = sheet;
- style.$$name = href;
- style.$$links = [link];
- link.parentNode.insertBefore(style, link);
- if (this.checkInlineThreshold(link, style, sheet)) {
- return;
- } // CSS loader is only injected for the first sheet, then this becomes an empty string
- let cssLoaderPreamble = "function $loadcss(u,m,l){(l=document.createElement('link')).rel='stylesheet';l.href=u;document.head.appendChild(l)}";
- const lazy = preloadMode === 'js-lazy';
- if (lazy) {
- cssLoaderPreamble = cssLoaderPreamble.replace('l.href', "l.media='print';l.onload=function(){l.media=m};l.href");
- } // Allow disabling any mutation of the stylesheet link:
- if (preloadMode === false) return;
- let noscriptFallback = false;
- if (preloadMode === 'body') {
- document.body.appendChild(link);
- } else {
- link.setAttribute('rel', 'preload');
- link.setAttribute('as', 'style');
- if (preloadMode === 'js' || preloadMode === 'js-lazy') {
- const script = document.createElement('script');
- const js = `${cssLoaderPreamble}$loadcss(${JSON.stringify(href)}${lazy ? ',' + JSON.stringify(media || 'all') : ''})`; // script.appendChild(document.createTextNode(js));
- script.textContent = js;
- link.parentNode.insertBefore(script, link.nextSibling);
- style.$$links.push(script);
- cssLoaderPreamble = '';
- noscriptFallback = true;
- } else if (preloadMode === 'media') {
- // @see https://github.com/filamentgroup/loadCSS/blob/af1106cfe0bf70147e22185afa7ead96c01dec48/src/loadCSS.js#L26
- link.setAttribute('rel', 'stylesheet');
- link.removeAttribute('as');
- link.setAttribute('media', 'print');
- link.setAttribute('onload', `this.media='${media || 'all'}'`);
- noscriptFallback = true;
- } else if (preloadMode === 'swap-high') {
- // @see http://filamentgroup.github.io/loadCSS/test/new-high.html
- link.setAttribute('rel', 'alternate stylesheet preload');
- link.setAttribute('title', 'styles');
- link.setAttribute('onload', `this.title='';this.rel='stylesheet'`);
- noscriptFallback = true;
- } else if (preloadMode === 'swap') {
- link.setAttribute('onload', "this.rel='stylesheet'");
- noscriptFallback = true;
- } else {
- const bodyLink = document.createElement('link');
- bodyLink.setAttribute('rel', 'stylesheet');
- if (media) bodyLink.setAttribute('media', media);
- bodyLink.setAttribute('href', href);
- document.body.appendChild(bodyLink);
- style.$$links.push(bodyLink);
- }
- }
- if (this.options.noscriptFallback !== false && noscriptFallback) {
- const noscript = document.createElement('noscript');
- const noscriptLink = document.createElement('link');
- noscriptLink.setAttribute('rel', 'stylesheet');
- noscriptLink.setAttribute('href', href);
- if (media) noscriptLink.setAttribute('media', media);
- noscript.appendChild(noscriptLink);
- link.parentNode.insertBefore(noscript, link.nextSibling);
- style.$$links.push(noscript);
- }
- }
- /**
- * Prune the source CSS files
- */
- pruneSource(style, before, sheetInverse) {
- // if external stylesheet would be below minimum size, just inline everything
- const minSize = this.options.minimumExternalSize;
- const name = style.$$name;
- if (minSize && sheetInverse.length < minSize) {
- this.logger.info(`\u001b[32mInlined all of ${name} (non-critical external stylesheet would have been ${sheetInverse.length}b, which was below the threshold of ${minSize})\u001b[39m`);
- style.textContent = before; // remove any associated external resources/loaders:
- if (style.$$links) {
- for (const link of style.$$links) {
- const parent = link.parentNode;
- if (parent) parent.removeChild(link);
- }
- }
- return true;
- }
- return false;
- }
- /**
- * Parse the stylesheet within a <style> element, then reduce it to contain only rules used by the document.
- */
- async processStyle(style, document) {
- if (style.$$reduce === false) return;
- const name = style.$$name ? style.$$name.replace(/^\//, '') : 'inline CSS';
- const options = this.options; // const document = style.ownerDocument;
- let keyframesMode = options.keyframes || 'critical'; // we also accept a boolean value for options.keyframes
- if (keyframesMode === true) keyframesMode = 'all';
- if (keyframesMode === false) keyframesMode = 'none';
- let sheet = style.textContent; // store a reference to the previous serialized stylesheet for reporting stats
- const before = sheet; // Skip empty stylesheets
- if (!sheet) return;
- const ast = parseStylesheet(sheet);
- const astInverse = options.pruneSource ? parseStylesheet(sheet) : null; // a string to search for font names (very loose)
- let criticalFonts = '';
- const failedSelectors = [];
- const criticalKeyframeNames = []; // Walk all CSS rules, marking unused rules with `.$$remove=true` for removal in the second pass.
- // This first pass is also used to collect font and keyframe usage used in the second pass.
- walkStyleRules(ast, markOnly(rule => {
- if (rule.type === 'rule') {
- // Filter the selector list down to only those match
- rule.filterSelectors(sel => {
- // Strip pseudo-elements and pseudo-classes, since we only care that their associated elements exist.
- // This means any selector for a pseudo-element or having a pseudo-class will be inlined if the rest of the selector matches.
- if (sel === ':root' || sel.match(/^::?(before|after)$/)) {
- return true;
- }
- sel = sel.replace(/(?<!\\)::?[a-z-]+(?![a-z-(])/gi, '').replace(/::?not\(\s*\)/g, '').trim();
- if (!sel) return false;
- try {
- return document.querySelector(sel) != null;
- } catch (e) {
- failedSelectors.push(sel + ' -> ' + e.message);
- return false;
- }
- }); // If there are no matched selectors, remove the rule:
- if (!rule.selector) {
- return false;
- }
- if (rule.nodes) {
- for (let i = 0; i < rule.nodes.length; i++) {
- const decl = rule.nodes[i]; // detect used fonts
- if (decl.prop && decl.prop.match(/\bfont(-family)?\b/i)) {
- criticalFonts += ' ' + decl.value;
- } // detect used keyframes
- if (decl.prop === 'animation' || decl.prop === 'animation-name') {
- // @todo: parse animation declarations and extract only the name. for now we'll do a lazy match.
- const names = decl.value.split(/\s+/);
- for (let j = 0; j < names.length; j++) {
- const name = names[j].trim();
- if (name) criticalKeyframeNames.push(name);
- }
- }
- }
- }
- } // keep font rules, they're handled in the second pass:
- if (rule.type === 'atrule' && rule.name === 'font-face') return; // If there are no remaining rules, remove the whole rule:
- const rules = rule.nodes && rule.nodes.filter(rule => !rule.$$remove);
- return !rules || rules.length !== 0;
- }));
- if (failedSelectors.length !== 0) {
- this.logger.warn(`${failedSelectors.length} rules skipped due to selector errors:\n ${failedSelectors.join('\n ')}`);
- }
- const shouldPreloadFonts = options.fonts === true || options.preloadFonts === true;
- const shouldInlineFonts = options.fonts !== false && options.inlineFonts === true;
- const preloadedFonts = []; // Second pass, using data picked up from the first
- walkStyleRulesWithReverseMirror(ast, astInverse, rule => {
- // remove any rules marked in the first pass
- if (rule.$$remove === true) return false;
- applyMarkedSelectors(rule); // prune @keyframes rules
- if (rule.type === 'atrule' && rule.name === 'keyframes') {
- if (keyframesMode === 'none') return false;
- if (keyframesMode === 'all') return true;
- return criticalKeyframeNames.indexOf(rule.params) !== -1;
- } // prune @font-face rules
- if (rule.type === 'atrule' && rule.name === 'font-face') {
- let family, src;
- for (let i = 0; i < rule.nodes.length; i++) {
- const decl = rule.nodes[i];
- if (decl.prop === 'src') {
- // @todo parse this properly and generate multiple preloads with type="font/woff2" etc
- src = (decl.value.match(/url\s*\(\s*(['"]?)(.+?)\1\s*\)/) || [])[2];
- } else if (decl.prop === 'font-family') {
- family = decl.value;
- }
- }
- if (src && shouldPreloadFonts && preloadedFonts.indexOf(src) === -1) {
- preloadedFonts.push(src);
- const preload = document.createElement('link');
- preload.setAttribute('rel', 'preload');
- preload.setAttribute('as', 'font');
- preload.setAttribute('crossorigin', 'anonymous');
- preload.setAttribute('href', src.trim());
- document.head.appendChild(preload);
- } // if we're missing info, if the font is unused, or if critical font inlining is disabled, remove the rule:
- if (!family || !src || criticalFonts.indexOf(family) === -1 || !shouldInlineFonts) {
- return false;
- }
- }
- });
- sheet = serializeStylesheet(ast, {
- compress: this.options.compress !== false
- }); // If all rules were removed, get rid of the style element entirely
- if (sheet.trim().length === 0) {
- if (style.parentNode) {
- style.remove();
- }
- return;
- }
- let afterText = '';
- let styleInlinedCompletely = false;
- if (options.pruneSource) {
- const sheetInverse = serializeStylesheet(astInverse, {
- compress: this.options.compress !== false
- });
- styleInlinedCompletely = this.pruneSource(style, before, sheetInverse);
- if (styleInlinedCompletely) {
- const percent = sheetInverse.length / before.length * 100;
- afterText = `, reducing non-inlined size ${percent | 0}% to ${prettyBytes(sheetInverse.length)}`;
- }
- } // replace the inline stylesheet with its critical'd counterpart
- if (!styleInlinedCompletely) {
- style.textContent = sheet;
- } // output stats
- const percent = sheet.length / before.length * 100 | 0;
- this.logger.info('\u001b[32mInlined ' + prettyBytes(sheet.length) + ' (' + percent + '% of original ' + prettyBytes(before.length) + ') of ' + name + afterText + '.\u001b[39m');
- }
- }
- module.exports = Critters;
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