projecte_ionic/node_modules/critters/src/index1.js
2022-02-09 18:30:03 +01:00

681 lines
24 KiB
JavaScript
Executable file

/**
* 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.
*/
import path from 'path';
import prettyBytes from 'pretty-bytes';
import sources from 'webpack-sources';
import postcss from 'postcss';
import cssnano from 'cssnano';
import log from 'webpack-log';
import minimatch from 'minimatch';
import { createDocument, serializeDocument, setNodeText } from './dom';
import {
parseStylesheet,
serializeStylesheet,
walkStyleRules,
walkStyleRulesWithReverseMirror,
markOnly,
applyMarkedSelectors,
} from './css';
import { tap } from './util';
// Used to annotate this plugin's hooks in Tappable invocations
const PLUGIN_NAME = 'critters-webpack-plugin';
/**
* The mechanism to use for lazy-loading stylesheets.
* _[JS]_ indicates that a strategy requires JavaScript (falls back to `<noscript>`).
*
* - **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. _[JS]_
* - **"swap":** Convert stylesheet links to preloads that swap to `rel="stylesheet"` once loaded. _[JS]_
* - **"js":** Inject an asynchronous CSS loader similar to [LoadCSS](https://github.com/filamentgroup/loadCSS) and use it to load stylesheets. _[JS]_
* - **"js-lazy":** Like `"js"`, but the stylesheet is disabled until fully loaded.
* @typedef {(default|'body'|'media'|'swap'|'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
*/
/**
* All optional. Pass them to `new Critters({ ... })`.
* @public
* @typedef Options
* @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: `true`)_
* @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 _(default: ``)_.
* @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"`)_
*/
/**
* Create a Critters plugin instance with the given options.
* @public
* @param {Options} options Options to control how Critters inlines CSS.
* @example
* // webpack.config.js
* module.exports = {
* plugins: [
* new Critters({
* // Outputs: <link rel="preload" onload="this.rel='stylesheet'">
* preload: 'swap',
*
* // Don't inline critical font-face rules, but preload the font URLs:
* preloadFonts: true
* })
* ]
* }
*/
export default class Critters {
/** @private */
constructor(options) {
this.options = Object.assign(
{ logLevel: 'info', externalStylesheets: [] },
options || {}
);
this.options.pruneSource = this.options.pruneSource !== false;
this.urlFilter = this.options.filter;
if (this.urlFilter instanceof RegExp) {
this.urlFilter = this.urlFilter.test.bind(this.urlFilter);
}
this.logger = log({
name: 'Critters',
unique: true,
level: this.options.logLevel,
});
}
/**
* Invoked by Webpack during plugin initialization
*/
apply(compiler) {
// hook into the compiler to get a Compilation instance...
tap(compiler, 'compilation', PLUGIN_NAME, false, (compilation) => {
// ... which is how we get an "after" hook into html-webpack-plugin's HTML generation.
if (
compilation.hooks &&
compilation.hooks.htmlWebpackPluginAfterHtmlProcessing
) {
tap(
compilation,
'html-webpack-plugin-after-html-processing',
PLUGIN_NAME,
true,
(htmlPluginData, callback) => {
this.process(compiler, compilation, htmlPluginData.html)
.then((html) => {
callback(null, { html });
})
.catch(callback);
}
);
} else {
// If html-webpack-plugin isn't used, process the first HTML asset as an optimize step
tap(
compilation,
'optimize-assets',
PLUGIN_NAME,
true,
(assets, callback) => {
let htmlAssetName;
for (const name in assets) {
if (name.match(/\.html$/)) {
htmlAssetName = name;
break;
}
}
if (!htmlAssetName) {
return callback(Error('Could not find HTML asset.'));
}
const html = assets[htmlAssetName].source();
if (!html) return callback(Error('Empty HTML asset.'));
this.process(compiler, compilation, String(html))
.then((html) => {
assets[htmlAssetName] = new sources.RawSource(html);
callback();
})
.catch(callback);
}
);
}
});
}
/**
* Read the contents of a file from Webpack's input filesystem
*/
readFile(compilation, filename) {
const fs = this.fs || compilation.outputFileSystem;
return new Promise((resolve, reject) => {
const callback = (err, data) => {
if (err) reject(err);
else resolve(data);
};
if (fs && fs.readFile) {
fs.readFile(filename, callback);
} else {
require('fs').readFile(filename, 'utf8', callback);
}
});
}
/**
* Apply critical CSS processing to html-webpack-plugin
*/
async process(compiler, compilation, html) {
const outputPath = compiler.options.output.path;
const publicPath = compiler.options.output.publicPath;
// Parse the generated HTML in a DOM we can mutate
const document = createDocument(html);
if (this.options.additionalStylesheets) {
const styleSheetsIncluded = [];
(this.options.additionalStylesheets || []).forEach((cssFile) => {
if (styleSheetsIncluded.includes(cssFile)) {
return;
}
styleSheetsIncluded.push(cssFile);
const webpackCssAssets = Object.keys(
compilation.assets
).filter((file) => minimatch(file, cssFile));
webpackCssAssets.map((asset) => {
const tag = document.createElement('style');
tag.innerHTML = compilation.assets[asset].source();
document.head.appendChild(tag);
});
});
}
// `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, compilation, outputPath, publicPath)
)
);
}
// go through all the style tags in the document and reduce them to only critical CSS
const styles = [].slice.call(document.querySelectorAll('style'));
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
return serializeDocument(document);
}
async mergeStylesheets(document) {
const styles = [].slice.call(document.querySelectorAll('style'));
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();
}
if (this.options.compress !== false) {
const before = sheet;
const processor = postcss([cssnano()]);
const result = await processor.process(before, { from: undefined });
// @todo sourcemap support (elsewhere first)
sheet = result.css;
}
setNodeText(first, sheet);
}
/**
* Inline the target stylesheet referred to by a <link rel="stylesheet"> (assuming it passes `options.filter`)
*/
async embedLinkedStylesheet(link, compilation, outputPath, publicPath) {
const href = link.getAttribute('href');
const media = link.getAttribute('media');
const document = link.ownerDocument;
const preloadMode = this.options.preload;
// skip filtered resources, or network resources if no filter is provided
if (this.urlFilter ? this.urlFilter(href) : href.match(/^(https?:)?\/\//)) {
return Promise.resolve();
}
// 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(/^\//, '');
}
const filename = path.resolve(outputPath, normalizedPath);
// try to find a matching asset by filename in webpack's output (not yet written to disk)
const relativePath = path
.relative(outputPath, filename)
.replace(/^\.\//, '');
const asset = compilation.assets[relativePath];
// Attempt to read from assets, falling back to a disk read
let sheet = asset && asset.source();
if (!sheet) {
try {
sheet = await this.readFile(compilation, filename);
this.logger.warn(
`Stylesheet "${relativePath}" not found in assets, but a file was located on disk.${
this.options.pruneSource
? ' This means pruneSource will not be applied.'
: ''
}`
);
} catch (e) {
this.logger.warn(`Unable to locate stylesheet: ${relativePath}`);
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`
);
}
// the reduced critical CSS gets injected into a new <style> tag
const style = document.createElement('style');
style.appendChild(document.createTextNode(sheet));
link.parentNode.insertBefore(style, link);
if (
this.options.inlineThreshold &&
sheet.length < this.options.inlineThreshold
) {
style.$$reduce = false;
this.logger.info(
`\u001b[32mInlined all of ${href} (${sheet.length} was below the threshold of ${this.options.inlineThreshold})\u001b[39m`
);
if (asset) {
delete compilation.assets[relativePath];
} else {
this.logger.warn(
` > ${href} was not found in assets. the resource may still be emitted but will be unreferenced.`
);
}
link.parentNode.removeChild(link);
return;
}
// drop references to webpack asset locations onto the tag, used for later reporting and in-place asset updates
style.$$name = href;
style.$$asset = asset;
style.$$assetName = relativePath;
style.$$assets = compilation.assets;
style.$$links = [link];
// 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));
link.parentNode.insertBefore(script, link.nextSibling);
style.$$links.push(script);
cssLoaderPreamble = '';
noscriptFallback = true;
} else if (preloadMode === 'media') {
// @see https://github.com/filamentgroup/loadCSS/blob/af1106cfe0bf70147e22185afa7ead96c01dec48/src/loadCSS.js#L26
link.setAttribute('rel', 'stylesheet');
link.removeAttribute('as');
link.setAttribute('media', 'print');
link.setAttribute('onload', `this.media='${media || 'all'}'`);
noscriptFallback = true;
} else if (preloadMode === 'swap') {
link.setAttribute('onload', "this.rel='stylesheet'");
noscriptFallback = true;
} else {
const bodyLink = document.createElement('link');
bodyLink.setAttribute('rel', 'stylesheet');
if (media) bodyLink.setAttribute('media', media);
bodyLink.setAttribute('href', href);
document.body.appendChild(bodyLink);
style.$$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.$$links.push(noscript);
}
}
/**
* Parse the stylesheet within a <style> element, then reduce it to contain only rules used by the document.
*/
async processStyle(style) {
if (style.$$reduce === false) return;
const name = style.$$name ? style.$$name.replace(/^\//, '') : 'inline CSS';
const options = this.options;
const document = style.ownerDocument;
const head = document.querySelector('head');
let keyframesMode = options.keyframes || 'critical';
// we also accept a boolean value for options.keyframes
if (keyframesMode === true) keyframesMode = 'all';
if (keyframesMode === false) keyframesMode = 'none';
// basically `.textContent`
let sheet =
style.childNodes.length > 0 &&
[].map.call(style.childNodes, (node) => node.nodeValue).join('\n');
// 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 `.$$remove=true` for removal in the second pass.
// This first pass is also used to collect font and keyframe usage used in the second pass.
walkStyleRules(
ast,
markOnly((rule) => {
if (rule.type === 'rule') {
// Filter the selector list down to only those match
rule.filterSelectors((sel) => {
// Strip pseudo-elements and pseudo-classes, since we only care that their associated elements exist.
// This means any selector for a pseudo-element or having a pseudo-class will be inlined if the rest of the selector matches.
if (sel !== ':root') {
sel = sel.replace(/(?:>\s*)?::?[a-z-]+\s*(\{|$)/gi, '$1').trim();
}
if (!sel) return false;
try {
return document.querySelector(sel) != null;
} catch (e) {
failedSelectors.push(sel + ' -> ' + e.message);
return false;
}
});
// If there are no matched selectors, remove the rule:
if (rule.selectors.length === 0) {
return false;
}
if (rule.declarations) {
for (let i = 0; i < rule.declarations.length; i++) {
const decl = rule.declarations[i];
// detect used fonts
if (decl.property && decl.property.match(/\bfont(-family)?\b/i)) {
criticalFonts += ' ' + decl.value;
}
// detect used keyframes
if (
decl.property === 'animation' ||
decl.property === 'animation-name'
) {
// @todo: parse animation declarations and extract only the name. for now we'll do a lazy match.
const names = decl.value.split(/\s+/);
for (let j = 0; j < names.length; j++) {
const name = names[j].trim();
if (name) criticalKeyframeNames.push(name);
}
}
}
}
}
// keep font rules, they're handled in the second pass:
if (rule.type === 'font-face') return;
// If there are no remaining rules, remove the whole rule:
const rules = rule.rules && rule.rules.filter((rule) => !rule.$$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 === 'keyframes') {
if (keyframesMode === 'none') return false;
if (keyframesMode === 'all') return true;
return criticalKeyframeNames.indexOf(rule.name) !== -1;
}
// prune @font-face rules
if (rule.type === 'font-face') {
let family, src;
for (let i = 0; i < rule.declarations.length; i++) {
const decl = rule.declarations[i];
if (decl.property === '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.property === '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());
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,
}).trim();
// If all rules were removed, get rid of the style element entirely
if (sheet.trim().length === 0) {
if (style.parentNode) {
style.parentNode.removeChild(style);
}
return;
}
let afterText = '';
if (options.pruneSource) {
const sheetInverse = serializeStylesheet(astInverse, {
compress: this.options.compress !== false,
});
const asset = style.$$asset;
if (asset) {
// if external stylesheet would be below minimum size, just inline everything
const minSize = this.options.minimumExternalSize;
if (minSize && sheetInverse.length < minSize) {
this.logger.info(
`\u001b[32mInlined all of ${name} (non-critical external stylesheet would have been ${sheetInverse.length}b, which was below the threshold of ${minSize})\u001b[39m`
);
setNodeText(style, before);
// remove any associated external resources/loaders:
if (style.$$links) {
for (const link of style.$$links) {
const parent = link.parentNode;
if (parent) parent.removeChild(link);
}
}
// delete the webpack asset:
delete style.$$assets[style.$$assetName];
return;
}
const percent = (sheetInverse.length / before.length) * 100;
afterText = `, reducing non-inlined size ${
percent | 0
}% to ${prettyBytes(sheetInverse.length)}`;
style.$$assets[style.$$assetName] = new sources.LineToLineMappedSource(
sheetInverse,
style.$$assetName,
before
);
} else {
this.logger.warn(
'pruneSource is enabled, but a style (' +
name +
') has no corresponding Webpack asset.'
);
}
}
// replace the inline stylesheet with its critical'd counterpart
setNodeText(style, 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'
);
}
}
// Original code picks 1 html and during prune removes CSS files from assets. What if theres another dependency
// Handle error when parsing stylesheet
// Most of our partner's CSS fails parsing
// JSDOM css parsing fails even when css.parse works