114 lines
5.4 KiB
JavaScript
114 lines
5.4 KiB
JavaScript
/* eslint-env es6:false */
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/*
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* Copyright (c) 2010 Arc90 Inc
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* This code is heavily based on Arc90's readability.js (1.7.1) script
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* available at: http://code.google.com/p/arc90labs-readability
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*/
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var REGEXPS = {
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// NOTE: These two regular expressions are duplicated in
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// Readability.js. Please keep both copies in sync.
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articleNegativeLookBehindCandidates: /breadcrumbs|breadcrumb|utils|trilist|_header/i,
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articleNegativeLookAheadCandidates: /outstream(.?)_|sub(.?)_|m_|omeda-promo-|in-article-advert|block-ad-.*|tl_/i,
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unlikelyCandidates: /\bad\b|ai2html|banner|breadcrumbs|breadcrumb|combx|comment|community|cover-wrap|disqus|extra|footer|gdpr|header|legends|menu|related|remark|replies|rss|shoutbox|sidebar|skyscraper|social|sponsor|supplemental|ad-break|agegate|pagination|pager(?!ow)|popup|yom-remote|copyright|keywords|outline|infinite-list|beta|recirculation|site-index|hide-for-print|post-end-share-cta|post-end-cta-full|post-footer|post-head|post-tag|li-date|main-navigation|programtic-ads|outstream_article|hfeed|comment-holder|back-to-top|show-up-next|onward-journey|topic-tracker|list-nav|block-ad-entity|adSpecs|gift-article-button|modal-title|in-story-masthead|share-tools|standard-dock|expanded-dock|margins-h|subscribe-dialog|icon|bumped|dvz-social-media-buttons|post-toc|mobile-menu|mobile-navbar|tl_article_header|mvp(-post)*-(add-story|soc(-mob)*-wrap)|w-condition-invisible|rich-text-block main w-richtext|rich-text-block_ataglance at-a-glance test w-richtext|PostsPage-commentsSection/i,
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// okMaybeItsACandidate: /and|article(?!-breadcrumb)|body|column|content|main|shadow|post-header/i,
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get okMaybeItsACandidate() {
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return new RegExp(`and|(?<!${this.articleNegativeLookAheadCandidates.source})article(?!-(${this.articleNegativeLookBehindCandidates.source}))|body|column|content|^(?!main-navigation|main-header)main|shadow|post-header|hfeed site|blog-posts hfeed|container-banners|menu-opacity|header-with-anchor-widget|commentOnSelection`, 'i')
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},
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};
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function isNodeVisible(node) {
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// Have to null-check node.style and node.className.indexOf to deal with SVG and MathML nodes.
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return (!node.style || node.style.display != "none")
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&& !node.hasAttribute("hidden")
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//check for "fallback-image" so that wikimedia math images are displayed
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&& (!node.hasAttribute("aria-hidden") || node.getAttribute("aria-hidden") != "true" || (node.className && node.className.indexOf && node.className.indexOf("fallback-image") !== -1));
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}
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/**
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* Decides whether or not the document is reader-able without parsing the whole thing.
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* @param {Object} options Configuration object.
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* @param {number} [options.minContentLength=140] The minimum node content length used to decide if the document is readerable.
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* @param {number} [options.minScore=20] The minumum cumulated 'score' used to determine if the document is readerable.
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* @param {Function} [options.visibilityChecker=isNodeVisible] The function used to determine if a node is visible.
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* @return {boolean} Whether or not we suspect Readability.parse() will suceeed at returning an article object.
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*/
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function isProbablyReaderable(doc, options = {}) {
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// For backward compatibility reasons 'options' can either be a configuration object or the function used
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// to determine if a node is visible.
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if (typeof options == "function") {
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options = { visibilityChecker: options };
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}
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var defaultOptions = { minScore: 20, minContentLength: 140, visibilityChecker: isNodeVisible };
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options = Object.assign(defaultOptions, options);
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var nodes = doc.querySelectorAll("p, pre, article");
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// Get <div> nodes which have <br> node(s) and append them into the `nodes` variable.
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// Some articles' DOM structures might look like
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// <div>
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// Sentences<br>
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// <br>
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// Sentences<br>
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// </div>
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var brNodes = doc.querySelectorAll("div > br");
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if (brNodes.length) {
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var set = new Set(nodes);
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[].forEach.call(brNodes, function (node) {
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set.add(node.parentNode);
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});
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nodes = Array.from(set);
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}
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var score = 0;
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// This is a little cheeky, we use the accumulator 'score' to decide what to return from
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// this callback:
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return [].some.call(nodes, function (node) {
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if (!options.visibilityChecker(node)) {
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return false;
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}
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var matchString = node.className + " " + node.id;
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if (REGEXPS.unlikelyCandidates.test(matchString) &&
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!REGEXPS.okMaybeItsACandidate.test(matchString)) {
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return false;
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}
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if (node.matches("li p")) {
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return false;
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}
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var textContentLength = node.textContent.trim().length;
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if (textContentLength < options.minContentLength) {
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return false;
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}
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score += Math.sqrt(textContentLength - options.minContentLength);
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if (score > options.minScore) {
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return true;
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}
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return false;
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});
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}
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if (typeof module === "object") {
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module.exports = isProbablyReaderable;
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}
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