Add scripts for distillability modelling

heuristics/distillable/extract_features.js

+return (function() {
+  function hasOGArticle() {
+    var elems = document.head.querySelectorAll(
+        'meta[property="og:type"],meta[name="og:type"]');
+    for (var i in elems) {
+      if (elems[i].content && elems[i].content.toUpperCase() == 'ARTICLE') {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  function isVisible(e) {
+    var bounds = e.getBoundingClientRect()
+    var style = window.getComputedStyle(e);
+    return !(
+      bounds.height == 0 || bounds.width == 0 ||
+      style.display == "none" ||
+      style.visibility == "hidden" ||
+      style.opacity == 0
+    )
+  }
+
+  function countVisible(nodes) {
+    var count = 0;
+    for (var i = 0; i < nodes.length; i++) {
+      var node = nodes[i];
+      if (!isVisible(node)) {
+        continue;
+      }
+      count++;
+    }
+    return count;
+  }
+
+  var unlikelyCandidates = /banner|combx|comment|community|disqus|extra|foot|header|menu|related|remark|rss|share|shoutbox|sidebar|skyscraper|sponsor|ad-break|agegate|pagination|pager|popup/i;
+  var okMaybeItsACandidate = /and|article|body|column|main|shadow/i;
+
+  function mozScore() {
+    return _mozScore(true, 0.5, 140, true, 1e100);
+  }
+
+  function _mozScore(trim, power, cut, excludeLi, saturate) {
+    var score = 0;
+
+    var nodes = document.querySelectorAll('p,pre')
+    for (var i = 0; i < nodes.length; i++) {
+      var node = nodes[i];
+      if (!isVisible(node)) {
+        continue;
+      }
+      var matchString = node.className + " " + node.id;
+      if (unlikelyCandidates.test(matchString) &&
+           !okMaybeItsACandidate.test(matchString)) {
+        continue;
+      }
+
+      if (excludeLi && node.matches && node.matches("li p")) {
+        continue;
+      }
+
+      var textContent = node.textContent;
+      if (trim) textContent = textContent.trim();
+      var textContentLength = textContent.length;
+      textContentLength = Math.min(saturate, textContentLength)
+      if (textContentLength < cut) {
+        continue;
+      }
+
+      score += Math.pow(textContentLength - cut, power);
+    }
+    return score;
+  }
+
+  var body = document.body;
+  return {
+     'opengraph': hasOGArticle(),
+     'url': document.location.href,
+     'title': document.title,
+     'numElements': body.querySelectorAll('*').length,
+     'numAnchors': body.querySelectorAll('a').length,
+     'numForms': body.querySelectorAll('form').length,
+     'numTextInput': body.querySelectorAll('input[type="text"]').length,
+     'numPasswordInput': body.querySelectorAll('input[type="password"]').length,
+     'numPPRE': body.querySelectorAll('p,pre').length,
+     'innerText': body.innerText,
+     'textContent': body.textContent,
+     'innerHTML': body.innerHTML,
+     'mozScore': _mozScore(true, 0.5, 140, true, 1e100),
+     'mozScoreAllSqrt': _mozScore(true, 0.5, 0, true, 1e100),
+     'mozScoreAllLinear': _mozScore(true, 1, 0, true, 1e100),
+     'mozScoreFast': _mozScore(false, 0.5, 140, true, 1000),
+     'mozScoreFastAllSqrt': _mozScore(false, 0.5, 0, true, 1000),
+     'mozScoreFastAllLinear': _mozScore(false, 1, 0, true, 1000),
+     'visibleElements': countVisible(body.querySelectorAll('*')),
+     'visiblePPRE': countVisible(body.querySelectorAll('p,pre')),
+  }
+})()