source: trip-planner-front/node_modules/critters/src/index1.js@ fa375fe

Last change on this file since fa375fe was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

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1/**
2 * Copyright 2018 Google LLC
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
5 * use this file except in compliance with the License. You may obtain a copy of
6 * the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations under
14 * the License.
15 */
16
17import path from 'path';
18import prettyBytes from 'pretty-bytes';
19import sources from 'webpack-sources';
20import postcss from 'postcss';
21import cssnano from 'cssnano';
22import log from 'webpack-log';
23import minimatch from 'minimatch';
24import { createDocument, serializeDocument, setNodeText } from './dom';
25import {
26 parseStylesheet,
27 serializeStylesheet,
28 walkStyleRules,
29 walkStyleRulesWithReverseMirror,
30 markOnly,
31 applyMarkedSelectors,
32} from './css';
33import { tap } from './util';
34
35// Used to annotate this plugin's hooks in Tappable invocations
36const PLUGIN_NAME = 'critters-webpack-plugin';
37
38/**
39 * The mechanism to use for lazy-loading stylesheets.
40 * _[JS]_ indicates that a strategy requires JavaScript (falls back to `<noscript>`).
41 *
42 * - **default:** Move stylesheet links to the end of the document and insert preload meta tags in their place.
43 * - **"body":** Move all external stylesheet links to the end of the document.
44 * - **"media":** Load stylesheets asynchronously by adding `media="not x"` and removing once loaded. _[JS]_
45 * - **"swap":** Convert stylesheet links to preloads that swap to `rel="stylesheet"` once loaded. _[JS]_
46 * - **"js":** Inject an asynchronous CSS loader similar to [LoadCSS](https://github.com/filamentgroup/loadCSS) and use it to load stylesheets. _[JS]_
47 * - **"js-lazy":** Like `"js"`, but the stylesheet is disabled until fully loaded.
48 * @typedef {(default|'body'|'media'|'swap'|'js'|'js-lazy')} PreloadStrategy
49 * @public
50 */
51
52/**
53 * Controls which keyframes rules are inlined.
54 *
55 * - **"critical":** _(default)_ inline keyframes rules that are used by the critical CSS.
56 * - **"all":** Inline all keyframes rules.
57 * - **"none":** Remove all keyframes rules.
58 * @typedef {('critical'|'all'|'none')} KeyframeStrategy
59 * @private
60 * @property {String} keyframes Which {@link KeyframeStrategy keyframe strategy} to use (default: `critical`)_
61 */
62
63/**
64 * Controls log level of the plugin. Specifies the level the logger should use. A logger will
65 * not produce output for any log level beneath the specified level. Available levels and order
66 * are:
67 *
68 * - **"info"** _(default)_
69 * - **"warn"**
70 * - **"error"**
71 * - **"trace"**
72 * - **"debug"**
73 * - **"silent"**
74 * @typedef {('info'|'warn'|'error'|'trace'|'debug'|'silent')} LogLevel
75 * @public
76 */
77
78/**
79 * All optional. Pass them to `new Critters({ ... })`.
80 * @public
81 * @typedef Options
82 * @property {Boolean} external Inline styles from external stylesheets _(default: `true`)_
83 * @property {Number} inlineThreshold Inline external stylesheets smaller than a given size _(default: `0`)_
84 * @property {Number} minimumExternalSize If the non-critical external stylesheet would be below this size, just inline it _(default: `0`)_
85 * @property {Boolean} pruneSource Remove inlined rules from the external stylesheet _(default: `true`)_
86 * @property {Boolean} mergeStylesheets Merged inlined stylesheets into a single <style> tag _(default: `true`)_
87 * @property {String[]} additionalStylesheets Glob for matching other stylesheets to be used while looking for critical CSS _(default: ``)_.
88 * @property {String} preload Which {@link PreloadStrategy preload strategy} to use
89 * @property {Boolean} noscriptFallback Add `<noscript>` fallback to JS-based strategies
90 * @property {Boolean} inlineFonts Inline critical font-face rules _(default: `false`)_
91 * @property {Boolean} preloadFonts Preloads critical fonts _(default: `true`)_
92 * @property {Boolean} fonts Shorthand for setting `inlineFonts`+`preloadFonts`
93 * - Values:
94 * - `true` to inline critical font-face rules and preload the fonts
95 * - `false` to don't inline any font-face rules and don't preload fonts
96 * @property {String} keyframes Controls which keyframes rules are inlined.
97 * - Values:
98 * - `"critical"`: _(default)_ inline keyframes rules used by the critical CSS
99 * - `"all"` inline all keyframes rules
100 * - `"none"` remove all keyframes rules
101 * @property {Boolean} compress Compress resulting critical CSS _(default: `true`)_
102 * @property {String} logLevel Controls {@link LogLevel log level} of the plugin _(default: `"info"`)_
103 */
104
105/**
106 * Create a Critters plugin instance with the given options.
107 * @public
108 * @param {Options} options Options to control how Critters inlines CSS.
109 * @example
110 * // webpack.config.js
111 * module.exports = {
112 * plugins: [
113 * new Critters({
114 * // Outputs: <link rel="preload" onload="this.rel='stylesheet'">
115 * preload: 'swap',
116 *
117 * // Don't inline critical font-face rules, but preload the font URLs:
118 * preloadFonts: true
119 * })
120 * ]
121 * }
122 */
123export default class Critters {
124 /** @private */
125 constructor(options) {
126 this.options = Object.assign(
127 { logLevel: 'info', externalStylesheets: [] },
128 options || {}
129 );
130 this.options.pruneSource = this.options.pruneSource !== false;
131 this.urlFilter = this.options.filter;
132 if (this.urlFilter instanceof RegExp) {
133 this.urlFilter = this.urlFilter.test.bind(this.urlFilter);
134 }
135 this.logger = log({
136 name: 'Critters',
137 unique: true,
138 level: this.options.logLevel,
139 });
140 }
141
142 /**
143 * Invoked by Webpack during plugin initialization
144 */
145 apply(compiler) {
146 // hook into the compiler to get a Compilation instance...
147 tap(compiler, 'compilation', PLUGIN_NAME, false, (compilation) => {
148 // ... which is how we get an "after" hook into html-webpack-plugin's HTML generation.
149 if (
150 compilation.hooks &&
151 compilation.hooks.htmlWebpackPluginAfterHtmlProcessing
152 ) {
153 tap(
154 compilation,
155 'html-webpack-plugin-after-html-processing',
156 PLUGIN_NAME,
157 true,
158 (htmlPluginData, callback) => {
159 this.process(compiler, compilation, htmlPluginData.html)
160 .then((html) => {
161 callback(null, { html });
162 })
163 .catch(callback);
164 }
165 );
166 } else {
167 // If html-webpack-plugin isn't used, process the first HTML asset as an optimize step
168 tap(
169 compilation,
170 'optimize-assets',
171 PLUGIN_NAME,
172 true,
173 (assets, callback) => {
174 let htmlAssetName;
175 for (const name in assets) {
176 if (name.match(/\.html$/)) {
177 htmlAssetName = name;
178 break;
179 }
180 }
181 if (!htmlAssetName) {
182 return callback(Error('Could not find HTML asset.'));
183 }
184 const html = assets[htmlAssetName].source();
185 if (!html) return callback(Error('Empty HTML asset.'));
186
187 this.process(compiler, compilation, String(html))
188 .then((html) => {
189 assets[htmlAssetName] = new sources.RawSource(html);
190 callback();
191 })
192 .catch(callback);
193 }
194 );
195 }
196 });
197 }
198
199 /**
200 * Read the contents of a file from Webpack's input filesystem
201 */
202 readFile(compilation, filename) {
203 const fs = this.fs || compilation.outputFileSystem;
204 return new Promise((resolve, reject) => {
205 const callback = (err, data) => {
206 if (err) reject(err);
207 else resolve(data);
208 };
209 if (fs && fs.readFile) {
210 fs.readFile(filename, callback);
211 } else {
212 require('fs').readFile(filename, 'utf8', callback);
213 }
214 });
215 }
216
217 /**
218 * Apply critical CSS processing to html-webpack-plugin
219 */
220 async process(compiler, compilation, html) {
221 const outputPath = compiler.options.output.path;
222 const publicPath = compiler.options.output.publicPath;
223
224 // Parse the generated HTML in a DOM we can mutate
225 const document = createDocument(html);
226
227 if (this.options.additionalStylesheets) {
228 const styleSheetsIncluded = [];
229 (this.options.additionalStylesheets || []).forEach((cssFile) => {
230 if (styleSheetsIncluded.includes(cssFile)) {
231 return;
232 }
233 styleSheetsIncluded.push(cssFile);
234 const webpackCssAssets = Object.keys(
235 compilation.assets
236 ).filter((file) => minimatch(file, cssFile));
237 webpackCssAssets.map((asset) => {
238 const tag = document.createElement('style');
239 tag.innerHTML = compilation.assets[asset].source();
240 document.head.appendChild(tag);
241 });
242 });
243 }
244
245 // `external:false` skips processing of external sheets
246 if (this.options.external !== false) {
247 const externalSheets = [].slice.call(
248 document.querySelectorAll('link[rel="stylesheet"]')
249 );
250 await Promise.all(
251 externalSheets.map((link) =>
252 this.embedLinkedStylesheet(link, compilation, outputPath, publicPath)
253 )
254 );
255 }
256
257 // go through all the style tags in the document and reduce them to only critical CSS
258 const styles = [].slice.call(document.querySelectorAll('style'));
259 await Promise.all(
260 styles.map((style) => this.processStyle(style, document))
261 );
262
263 if (this.options.mergeStylesheets !== false && styles.length !== 0) {
264 await this.mergeStylesheets(document);
265 }
266
267 // serialize the document back to HTML and we're done
268 return serializeDocument(document);
269 }
270
271 async mergeStylesheets(document) {
272 const styles = [].slice.call(document.querySelectorAll('style'));
273 if (styles.length === 0) {
274 this.logger.warn(
275 'Merging inline stylesheets into a single <style> tag skipped, no inline stylesheets to merge'
276 );
277 return;
278 }
279 const first = styles[0];
280 let sheet = first.textContent;
281 for (let i = 1; i < styles.length; i++) {
282 const node = styles[i];
283 sheet += node.textContent;
284 node.remove();
285 }
286 if (this.options.compress !== false) {
287 const before = sheet;
288 const processor = postcss([cssnano()]);
289 const result = await processor.process(before, { from: undefined });
290 // @todo sourcemap support (elsewhere first)
291 sheet = result.css;
292 }
293 setNodeText(first, sheet);
294 }
295
296 /**
297 * Inline the target stylesheet referred to by a <link rel="stylesheet"> (assuming it passes `options.filter`)
298 */
299 async embedLinkedStylesheet(link, compilation, outputPath, publicPath) {
300 const href = link.getAttribute('href');
301 const media = link.getAttribute('media');
302 const document = link.ownerDocument;
303
304 const preloadMode = this.options.preload;
305
306 // skip filtered resources, or network resources if no filter is provided
307 if (this.urlFilter ? this.urlFilter(href) : href.match(/^(https?:)?\/\//)) {
308 return Promise.resolve();
309 }
310
311 // path on disk (with output.publicPath removed)
312 let normalizedPath = href.replace(/^\//, '');
313 const pathPrefix = (publicPath || '').replace(/(^\/|\/$)/g, '') + '/';
314 if (normalizedPath.indexOf(pathPrefix) === 0) {
315 normalizedPath = normalizedPath
316 .substring(pathPrefix.length)
317 .replace(/^\//, '');
318 }
319 const filename = path.resolve(outputPath, normalizedPath);
320
321 // try to find a matching asset by filename in webpack's output (not yet written to disk)
322 const relativePath = path
323 .relative(outputPath, filename)
324 .replace(/^\.\//, '');
325 const asset = compilation.assets[relativePath];
326
327 // Attempt to read from assets, falling back to a disk read
328 let sheet = asset && asset.source();
329 if (!sheet) {
330 try {
331 sheet = await this.readFile(compilation, filename);
332 this.logger.warn(
333 `Stylesheet "${relativePath}" not found in assets, but a file was located on disk.${
334 this.options.pruneSource
335 ? ' This means pruneSource will not be applied.'
336 : ''
337 }`
338 );
339 } catch (e) {
340 this.logger.warn(`Unable to locate stylesheet: ${relativePath}`);
341 return;
342 }
343 }
344
345 // CSS loader is only injected for the first sheet, then this becomes an empty string
346 let cssLoaderPreamble = `function $loadcss(u,m,l){(l=document.createElement('link')).rel='stylesheet';l.href=u;document.head.appendChild(l)}`;
347 const lazy = preloadMode === 'js-lazy';
348 if (lazy) {
349 cssLoaderPreamble = cssLoaderPreamble.replace(
350 'l.href',
351 `l.media='print';l.onload=function(){l.media=m};l.href`
352 );
353 }
354
355 // the reduced critical CSS gets injected into a new <style> tag
356 const style = document.createElement('style');
357 style.appendChild(document.createTextNode(sheet));
358 link.parentNode.insertBefore(style, link);
359
360 if (
361 this.options.inlineThreshold &&
362 sheet.length < this.options.inlineThreshold
363 ) {
364 style.$$reduce = false;
365 this.logger.info(
366 `\u001b[32mInlined all of ${href} (${sheet.length} was below the threshold of ${this.options.inlineThreshold})\u001b[39m`
367 );
368 if (asset) {
369 delete compilation.assets[relativePath];
370 } else {
371 this.logger.warn(
372 ` > ${href} was not found in assets. the resource may still be emitted but will be unreferenced.`
373 );
374 }
375 link.parentNode.removeChild(link);
376 return;
377 }
378
379 // drop references to webpack asset locations onto the tag, used for later reporting and in-place asset updates
380 style.$$name = href;
381 style.$$asset = asset;
382 style.$$assetName = relativePath;
383 style.$$assets = compilation.assets;
384 style.$$links = [link];
385
386 // Allow disabling any mutation of the stylesheet link:
387 if (preloadMode === false) return;
388
389 let noscriptFallback = false;
390
391 if (preloadMode === 'body') {
392 document.body.appendChild(link);
393 } else {
394 link.setAttribute('rel', 'preload');
395 link.setAttribute('as', 'style');
396 if (preloadMode === 'js' || preloadMode === 'js-lazy') {
397 const script = document.createElement('script');
398 const js = `${cssLoaderPreamble}$loadcss(${JSON.stringify(href)}${
399 lazy ? ',' + JSON.stringify(media || 'all') : ''
400 })`;
401 script.appendChild(document.createTextNode(js));
402 link.parentNode.insertBefore(script, link.nextSibling);
403 style.$$links.push(script);
404 cssLoaderPreamble = '';
405 noscriptFallback = true;
406 } else if (preloadMode === 'media') {
407 // @see https://github.com/filamentgroup/loadCSS/blob/af1106cfe0bf70147e22185afa7ead96c01dec48/src/loadCSS.js#L26
408 link.setAttribute('rel', 'stylesheet');
409 link.removeAttribute('as');
410 link.setAttribute('media', 'print');
411 link.setAttribute('onload', `this.media='${media || 'all'}'`);
412 noscriptFallback = true;
413 } else if (preloadMode === 'swap') {
414 link.setAttribute('onload', "this.rel='stylesheet'");
415 noscriptFallback = true;
416 } else {
417 const bodyLink = document.createElement('link');
418 bodyLink.setAttribute('rel', 'stylesheet');
419 if (media) bodyLink.setAttribute('media', media);
420 bodyLink.setAttribute('href', href);
421 document.body.appendChild(bodyLink);
422 style.$$links.push(bodyLink);
423 }
424 }
425
426 if (this.options.noscriptFallback !== false && noscriptFallback) {
427 const noscript = document.createElement('noscript');
428 const noscriptLink = document.createElement('link');
429 noscriptLink.setAttribute('rel', 'stylesheet');
430 noscriptLink.setAttribute('href', href);
431 if (media) noscriptLink.setAttribute('media', media);
432 noscript.appendChild(noscriptLink);
433 link.parentNode.insertBefore(noscript, link.nextSibling);
434 style.$$links.push(noscript);
435 }
436 }
437
438 /**
439 * Parse the stylesheet within a <style> element, then reduce it to contain only rules used by the document.
440 */
441 async processStyle(style) {
442 if (style.$$reduce === false) return;
443
444 const name = style.$$name ? style.$$name.replace(/^\//, '') : 'inline CSS';
445 const options = this.options;
446 const document = style.ownerDocument;
447 const head = document.querySelector('head');
448 let keyframesMode = options.keyframes || 'critical';
449 // we also accept a boolean value for options.keyframes
450 if (keyframesMode === true) keyframesMode = 'all';
451 if (keyframesMode === false) keyframesMode = 'none';
452
453 // basically `.textContent`
454 let sheet =
455 style.childNodes.length > 0 &&
456 [].map.call(style.childNodes, (node) => node.nodeValue).join('\n');
457
458 // store a reference to the previous serialized stylesheet for reporting stats
459 const before = sheet;
460
461 // Skip empty stylesheets
462 if (!sheet) return;
463
464 const ast = parseStylesheet(sheet);
465 const astInverse = options.pruneSource ? parseStylesheet(sheet) : null;
466
467 // a string to search for font names (very loose)
468 let criticalFonts = '';
469
470 const failedSelectors = [];
471
472 const criticalKeyframeNames = [];
473
474 // Walk all CSS rules, marking unused rules with `.$$remove=true` for removal in the second pass.
475 // This first pass is also used to collect font and keyframe usage used in the second pass.
476 walkStyleRules(
477 ast,
478 markOnly((rule) => {
479 if (rule.type === 'rule') {
480 // Filter the selector list down to only those match
481 rule.filterSelectors((sel) => {
482 // Strip pseudo-elements and pseudo-classes, since we only care that their associated elements exist.
483 // This means any selector for a pseudo-element or having a pseudo-class will be inlined if the rest of the selector matches.
484 if (sel !== ':root') {
485 sel = sel.replace(/(?:>\s*)?::?[a-z-]+\s*(\{|$)/gi, '$1').trim();
486 }
487 if (!sel) return false;
488
489 try {
490 return document.querySelector(sel) != null;
491 } catch (e) {
492 failedSelectors.push(sel + ' -> ' + e.message);
493 return false;
494 }
495 });
496 // If there are no matched selectors, remove the rule:
497 if (rule.selectors.length === 0) {
498 return false;
499 }
500
501 if (rule.declarations) {
502 for (let i = 0; i < rule.declarations.length; i++) {
503 const decl = rule.declarations[i];
504
505 // detect used fonts
506 if (decl.property && decl.property.match(/\bfont(-family)?\b/i)) {
507 criticalFonts += ' ' + decl.value;
508 }
509
510 // detect used keyframes
511 if (
512 decl.property === 'animation' ||
513 decl.property === 'animation-name'
514 ) {
515 // @todo: parse animation declarations and extract only the name. for now we'll do a lazy match.
516 const names = decl.value.split(/\s+/);
517 for (let j = 0; j < names.length; j++) {
518 const name = names[j].trim();
519 if (name) criticalKeyframeNames.push(name);
520 }
521 }
522 }
523 }
524 }
525
526 // keep font rules, they're handled in the second pass:
527 if (rule.type === 'font-face') return;
528
529 // If there are no remaining rules, remove the whole rule:
530 const rules = rule.rules && rule.rules.filter((rule) => !rule.$$remove);
531 return !rules || rules.length !== 0;
532 })
533 );
534
535 if (failedSelectors.length !== 0) {
536 this.logger.warn(
537 `${
538 failedSelectors.length
539 } rules skipped due to selector errors:\n ${failedSelectors.join(
540 '\n '
541 )}`
542 );
543 }
544
545 const shouldPreloadFonts =
546 options.fonts === true || options.preloadFonts === true;
547 const shouldInlineFonts =
548 options.fonts !== false && options.inlineFonts === true;
549
550 const preloadedFonts = [];
551 // Second pass, using data picked up from the first
552 walkStyleRulesWithReverseMirror(ast, astInverse, (rule) => {
553 // remove any rules marked in the first pass
554 if (rule.$$remove === true) return false;
555
556 applyMarkedSelectors(rule);
557
558 // prune @keyframes rules
559 if (rule.type === 'keyframes') {
560 if (keyframesMode === 'none') return false;
561 if (keyframesMode === 'all') return true;
562 return criticalKeyframeNames.indexOf(rule.name) !== -1;
563 }
564
565 // prune @font-face rules
566 if (rule.type === 'font-face') {
567 let family, src;
568 for (let i = 0; i < rule.declarations.length; i++) {
569 const decl = rule.declarations[i];
570 if (decl.property === 'src') {
571 // @todo parse this properly and generate multiple preloads with type="font/woff2" etc
572 src = (decl.value.match(/url\s*\(\s*(['"]?)(.+?)\1\s*\)/) || [])[2];
573 } else if (decl.property === 'font-family') {
574 family = decl.value;
575 }
576 }
577
578 if (src && shouldPreloadFonts && preloadedFonts.indexOf(src) === -1) {
579 preloadedFonts.push(src);
580 const preload = document.createElement('link');
581 preload.setAttribute('rel', 'preload');
582 preload.setAttribute('as', 'font');
583 preload.setAttribute('crossorigin', 'anonymous');
584 preload.setAttribute('href', src.trim());
585 head.appendChild(preload);
586 }
587
588 // if we're missing info, if the font is unused, or if critical font inlining is disabled, remove the rule:
589 if (
590 !family ||
591 !src ||
592 criticalFonts.indexOf(family) === -1 ||
593 !shouldInlineFonts
594 ) {
595 return false;
596 }
597 }
598 });
599
600 sheet = serializeStylesheet(ast, {
601 compress: this.options.compress !== false,
602 }).trim();
603
604 // If all rules were removed, get rid of the style element entirely
605 if (sheet.trim().length === 0) {
606 if (style.parentNode) {
607 style.parentNode.removeChild(style);
608 }
609 return;
610 }
611
612 let afterText = '';
613 if (options.pruneSource) {
614 const sheetInverse = serializeStylesheet(astInverse, {
615 compress: this.options.compress !== false,
616 });
617 const asset = style.$$asset;
618 if (asset) {
619 // if external stylesheet would be below minimum size, just inline everything
620 const minSize = this.options.minimumExternalSize;
621 if (minSize && sheetInverse.length < minSize) {
622 this.logger.info(
623 `\u001b[32mInlined all of ${name} (non-critical external stylesheet would have been ${sheetInverse.length}b, which was below the threshold of ${minSize})\u001b[39m`
624 );
625 setNodeText(style, before);
626 // remove any associated external resources/loaders:
627 if (style.$$links) {
628 for (const link of style.$$links) {
629 const parent = link.parentNode;
630 if (parent) parent.removeChild(link);
631 }
632 }
633 // delete the webpack asset:
634 delete style.$$assets[style.$$assetName];
635 return;
636 }
637
638 const percent = (sheetInverse.length / before.length) * 100;
639 afterText = `, reducing non-inlined size ${
640 percent | 0
641 }% to ${prettyBytes(sheetInverse.length)}`;
642 style.$$assets[style.$$assetName] = new sources.LineToLineMappedSource(
643 sheetInverse,
644 style.$$assetName,
645 before
646 );
647 } else {
648 this.logger.warn(
649 'pruneSource is enabled, but a style (' +
650 name +
651 ') has no corresponding Webpack asset.'
652 );
653 }
654 }
655
656 // replace the inline stylesheet with its critical'd counterpart
657 setNodeText(style, sheet);
658
659 // output stats
660 const percent = ((sheet.length / before.length) * 100) | 0;
661 this.logger.info(
662 '\u001b[32mInlined ' +
663 prettyBytes(sheet.length) +
664 ' (' +
665 percent +
666 '% of original ' +
667 prettyBytes(before.length) +
668 ') of ' +
669 name +
670 afterText +
671 '.\u001b[39m'
672 );
673 }
674}
675
676// Original code picks 1 html and during prune removes CSS files from assets. What if theres another dependency
677// Handle error when parsing stylesheet
678// Most of our partner's CSS fails parsing
679// JSDOM css parsing fails even when css.parse works
680
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