text: /* eslint-env es6:false */
  /* globals exports */
  /*
   * 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|main|shadow/i,
  };
  
  function isNodeVisible(node) {
      // Have to null-check node.style to deal with SVG and MathML nodes.
      return (!node.style || node.style.display != "none") && !node.hasAttribute("hidden")
          && (!node.hasAttribute("aria-hidden") || node.getAttribute("aria-hidden") != "true");
  }
  
  /**
   * Decides whether or not the document is reader-able without parsing the whole thing.
   *
   * @return boolean Whether or not we suspect Readability.parse() will suceeed at returning an article object.
   */
  function isProbablyReaderable(doc, isVisible) {
      if (!isVisible) {
          isVisible = isNodeVisible;
      }
  
      var nodes = doc.querySelectorAll("p, pre");
  
      // 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 (!isVisible(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 < 140) {
              return false;
          }
  
          score += Math.sqrt(textContentLength - 140);
  
          //Old value was 20
          if (score > 30) {
              return true;
          }
          return false;
      });
  }