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- /* eslint-env es6:false */
- /*
- * Copyright (c) 2010 Arc90 Inc
- *
- * 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.
- */
- /*
- * This code is heavily based on Arc90's readability.js (1.7.1) script
- * available at: http://code.google.com/p/arc90labs-readability
- */
- var REGEXPS = {
- // NOTE: These two regular expressions are duplicated in
- // Readability.js. Please keep both copies in sync.
- unlikelyCandidates: /-ad-|ai2html|banner|breadcrumbs|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|popup|yom-remote/i,
- okMaybeItsACandidate: /and|article|body|column|content|main|shadow/i,
- };
- function isNodeVisible(node) {
- // Have to null-check node.style and node.className.indexOf to deal with SVG and MathML nodes.
- return (!node.style || node.style.display != "none")
- && !node.hasAttribute("hidden")
- //check for "fallback-image" so that wikimedia math images are displayed
- && (!node.hasAttribute("aria-hidden") || node.getAttribute("aria-hidden") != "true" || (node.className && node.className.indexOf && node.className.indexOf("fallback-image") !== -1));
- }
- /**
- * Decides whether or not the document is reader-able without parsing the whole thing.
- * @param {Object} options Configuration object.
- * @param {number} [options.minContentLength=140] The minimum node content length used to decide if the document is readerable.
- * @param {number} [options.minScore=20] The minumum cumulated 'score' used to determine if the document is readerable.
- * @param {Function} [options.visibilityChecker=isNodeVisible] The function used to determine if a node is visible.
- * @return {boolean} Whether or not we suspect Readability.parse() will suceeed at returning an article object.
- */
- function isProbablyReaderable(doc, options = {}) {
- // For backward compatibility reasons 'options' can either be a configuration object or the function used
- // to determine if a node is visible.
- if (typeof options == "function") {
- options = { visibilityChecker: options };
- }
- var defaultOptions = { minScore: 20, minContentLength: 140, visibilityChecker: isNodeVisible };
- options = Object.assign(defaultOptions, options);
- var nodes = doc.querySelectorAll("p, pre, article");
- // Get <div> nodes which have <br> node(s) and append them into the `nodes` variable.
- // Some articles' DOM structures might look like
- // <div>
- // Sentences<br>
- // <br>
- // Sentences<br>
- // </div>
- var brNodes = doc.querySelectorAll("div > br");
- if (brNodes.length) {
- var set = new Set(nodes);
- [].forEach.call(brNodes, function (node) {
- set.add(node.parentNode);
- });
- nodes = Array.from(set);
- }
- var score = 0;
- // This is a little cheeky, we use the accumulator 'score' to decide what to return from
- // this callback:
- return [].some.call(nodes, function (node) {
- if (!options.visibilityChecker(node)) {
- return false;
- }
- var matchString = node.className + " " + node.id;
- if (REGEXPS.unlikelyCandidates.test(matchString) &&
- !REGEXPS.okMaybeItsACandidate.test(matchString)) {
- return false;
- }
- if (node.matches("li p")) {
- return false;
- }
- var textContentLength = node.textContent.trim().length;
- if (textContentLength < options.minContentLength) {
- return false;
- }
- score += Math.sqrt(textContentLength - options.minContentLength);
- if (score > options.minScore) {
- return true;
- }
- return false;
- });
- }
- if (typeof module === "object") {
- module.exports = isProbablyReaderable;
- }
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