From 69ae30875d10dc8af3f8f087ca60824be0701f96 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felix=20B=C3=B6hm?= <me@feedic.com>
Date: Thu, 24 Dec 2020 10:38:22 +0100
Subject: [PATCH] refactor: Declare vars when used, streamline code (#1588)

* Remove unnecessary branches
* Improve comments
* Declare vars when used
* Use `function` statements
* Use `domEach` where appropriate
* Disallow shadowing, use before define
---
 .eslintrc.json           |   2 +
 benchmark/suite.js       |  18 ++----
 lib/api/attributes.js    | 132 +++++++++++++++------------------------
 lib/api/forms.js         |   3 +-
 lib/api/manipulation.js  | 108 +++++++++++---------------------
 lib/api/traversing.js    |  59 ++++++++---------
 lib/cheerio.js           |  20 +++---
 lib/parse.js             |  41 +++++-------
 lib/static.js            |  17 +++--
 test/api/deprecated.js   |  10 +--
 test/api/manipulation.js |  93 ++++++++++-----------------
 test/api/utils.js        |   6 +-
 test/cheerio.js          |  10 ++-
 test/xml.js              |   8 +--
 types/index.d.ts         |   2 +-
 15 files changed, 204 insertions(+), 325 deletions(-)

diff --git a/.eslintrc.json b/.eslintrc.json
index de402a4593..163436541d 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -11,6 +11,8 @@
     "curly": [2, "multi-line"],
     "one-var": [2, "never"],
     "no-else-return": 2,
+    "no-shadow": 2,
+    "no-use-before-define": [2, "nofunc"],
 
     "jsdoc/check-param-names": 2,
     "jsdoc/check-tag-names": 2,
diff --git a/benchmark/suite.js b/benchmark/suite.js
index 59d1c5e193..47c2114f54 100644
--- a/benchmark/suite.js
+++ b/benchmark/suite.js
@@ -25,13 +25,11 @@ Suites.prototype.cheerioOnly = function () {
 };
 
 Suites.prototype.add = function (name, fileName, options) {
-  var markup;
-  var suite;
   if (!filterRe.test(name)) {
     return;
   }
-  markup = fs.readFileSync(path.join(documentDir, fileName), 'utf8');
-  suite = new Benchmark.Suite(name);
+  var markup = fs.readFileSync(path.join(documentDir, fileName), 'utf8');
+  var suite = new Benchmark.Suite(name);
 
   suite.on('start', function () {
     console.log('Test: ' + name + ' (file: ' + fileName + ')');
@@ -70,10 +68,8 @@ Suites.prototype._benchJsDom = function (suite, markup, options) {
 
   jQueryScript.runInContext(dom.getInternalVMContext());
 
-  var setupData;
-  if (options.setup) {
-    setupData = options.setup.call(null, dom.window.$);
-  }
+  var setupData = options.setup && options.setup.call(null, dom.window.$);
+
   suite.add('jsdom', function () {
     testFn.call(null, dom.window.$, setupData);
   });
@@ -83,10 +79,8 @@ Suites.prototype._benchJsDom = function (suite, markup, options) {
 Suites.prototype._benchCheerio = function (suite, markup, options) {
   var $ = cheerio.load(markup);
   var testFn = options.test;
-  var setupData;
-  if (options.setup) {
-    setupData = options.setup.call(null, $);
-  }
+  var setupData = options.setup && options.setup.call(null, $);
+
   suite.add('cheerio', function () {
     testFn.call(null, $, setupData);
   });
diff --git a/lib/api/attributes.js b/lib/api/attributes.js
index 07162d1903..6d46aaad0f 100644
--- a/lib/api/attributes.js
+++ b/lib/api/attributes.js
@@ -25,7 +25,7 @@ var rboolean = /^(?:autofocus|autoplay|async|checked|controls|defer|disabled|hid
 // Matches strings that look like JSON objects or arrays
 var rbrace = /^(?:\{[\w\W]*\}|\[[\w\W]*\])$/;
 
-var getAttr = function (elem, name) {
+function getAttr(elem, name) {
   if (!elem || !isTag(elem)) return;
 
   if (!elem.attribs) {
@@ -55,15 +55,15 @@ var getAttr = function (elem, name) {
   ) {
     return 'on';
   }
-};
+}
 
-var setAttr = function (el, name, value) {
+function setAttr(el, name, value) {
   if (value === null) {
     removeAttribute(el, name);
   } else {
     el.attribs[name] = value + '';
   }
-};
+}
 
 /**
  * Method for getting and setting attributes. Gets the attribute value for only
@@ -109,7 +109,7 @@ exports.attr = function (name, value) {
   return getAttr(this[0], name);
 };
 
-var getProp = function (el, name) {
+function getProp(el, name) {
   if (!el || !isTag(el)) return;
 
   return name in el
@@ -117,15 +117,15 @@ var getProp = function (el, name) {
     : rboolean.test(name)
     ? getAttr(el, name) !== undefined
     : getAttr(el, name);
-};
+}
 
-var setProp = function (el, name, value) {
+function setProp(el, name, value) {
   if (name in el) {
     el[name] = value;
   } else {
     setAttr(el, name, rboolean.test(name) ? (value ? '' : null) : value);
   }
-};
+}
 
 /**
  * Method for getting and setting properties. Gets the property value for only
@@ -145,21 +145,19 @@ var setProp = function (el, name, value) {
  * @see {@link http://api.jquery.com/prop/}
  */
 exports.prop = function (name, value) {
-  var i = 0;
-  var property;
-
   if (typeof name === 'string' && value === undefined) {
     switch (name) {
-      case 'style':
-        property = this.css();
-
-        Object.keys(property).forEach(function (p) {
-          property[i++] = p;
+      case 'style': {
+        var property = this.css();
+        var keys = Object.keys(property);
+        keys.forEach(function (p, i) {
+          property[i] = p;
         });
 
-        property.length = i;
+        property.length = keys.length;
 
         break;
+      }
       case 'tagName':
       case 'nodeName':
         property = this[0].name.toUpperCase();
@@ -199,7 +197,7 @@ exports.prop = function (name, value) {
   }
 };
 
-var setData = function (el, name, value) {
+function setData(el, name, value) {
   if (!el.data) {
     el.data = {};
   }
@@ -208,21 +206,16 @@ var setData = function (el, name, value) {
   if (typeof name === 'string' && value !== undefined) {
     el.data[name] = value;
   }
-};
+}
 
 // Read the specified attribute from the equivalent HTML5 `data-*` attribute,
 // and (if present) cache the value in the node's internal data store. If no
 // attribute name is specified, read *all* HTML5 `data-*` attributes in this
 // manner.
-var readData = function (el, name) {
+function readData(el, name) {
   var readAll = arguments.length === 1;
   var domNames;
-  var domName;
   var jsNames;
-  var jsName;
-  var value;
-  var idx;
-  var length;
 
   if (readAll) {
     domNames = Object.keys(el.attribs).filter(function (attrName) {
@@ -236,9 +229,10 @@ var readData = function (el, name) {
     jsNames = [name];
   }
 
-  for (idx = 0, length = domNames.length; idx < length; ++idx) {
-    domName = domNames[idx];
-    jsName = jsNames[idx];
+  for (var idx = 0; idx < domNames.length; ++idx) {
+    var domName = domNames[idx];
+    var jsName = jsNames[idx];
+    var value;
     if (hasOwn.call(el.attribs, domName) && !hasOwn.call(el.data, jsName)) {
       value = el.attribs[domName];
 
@@ -259,7 +253,7 @@ var readData = function (el, name) {
   }
 
   return readAll ? el.data : value;
-};
+}
 
 /**
  * Method for getting and setting data attributes. Gets or sets the data
@@ -334,20 +328,11 @@ exports.val = function (value) {
   switch (element.name) {
     case 'textarea':
       return this.text(value);
-    case 'input':
-      if (querying) {
-        return this.attr('value');
-      }
-
-      this.attr('value', value);
-      return this;
-
-    case 'select':
+    case 'select': {
       var option = this.find('option:selected');
-      var returnValue;
-      if (option === undefined) return undefined;
+      if (!option) return undefined;
       if (!querying) {
-        if (!hasOwn.call(this.attr(), 'multiple') && typeof value == 'object') {
+        if (this.attr('multiple') == null && typeof value == 'object') {
           return this;
         }
         if (typeof value != 'object') {
@@ -359,20 +344,16 @@ exports.val = function (value) {
         }
         return this;
       }
-      returnValue = option.attr('value');
-      if (hasOwn.call(this.attr(), 'multiple')) {
-        returnValue = [];
-        domEach(option, function (__, el) {
-          returnValue.push(getAttr(el, 'value'));
-        });
-      }
-      return returnValue;
+
+      return this.attr('multiple')
+        ? option.toArray().map(function (el) {
+            return getAttr(el, 'value');
+          })
+        : option.attr('value');
+    }
+    case 'input':
     case 'option':
-      if (!querying) {
-        this.attr('value', value);
-        return this;
-      }
-      return this.attr('value');
+      return querying ? this.attr('value') : this.attr('value', value);
   }
 };
 
@@ -383,11 +364,11 @@ exports.val = function (value) {
  * @param {node} elem - Node to remove attribute from.
  * @param {string} name - Name of the attribute to remove.
  */
-var removeAttribute = function (elem, name) {
+function removeAttribute(elem, name) {
   if (!elem.attribs || !hasOwn.call(elem.attribs, name)) return;
 
   delete elem.attribs[name];
-};
+}
 
 /**
  * Splits a space-separated list of names to individual
@@ -396,9 +377,9 @@ var removeAttribute = function (elem, name) {
  * @param {string} names -  Names to split.
  * @returns {string[]} - Split names.
  */
-var splitNames = function (names) {
+function splitNames(names) {
   return names ? names.trim().split(rspace) : [];
-};
+}
 
 /**
  * Method for removing attributes by `name`.
@@ -443,19 +424,18 @@ exports.removeAttr = function (name) {
  * //=> true
  *
  * @param {string} className - Name of the class.
+ * @returns {boolean}
  *
  * @see {@link http://api.jquery.com/hasClass/}
  */
 exports.hasClass = function (className) {
   return this.toArray().some(function (elem) {
-    var attrs = elem.attribs;
-    var clazz = attrs && attrs['class'];
+    var clazz = elem.attribs && elem.attribs['class'];
     var idx = -1;
-    var end;
 
     if (clazz && className.length) {
       while ((idx = clazz.indexOf(className, idx + 1)) > -1) {
-        end = idx + className.length;
+        var end = idx + className.length;
 
         if (
           (idx === 0 || rspace.test(clazz[idx - 1])) &&
@@ -505,17 +485,14 @@ exports.addClass = function (value) {
 
     // If we don't already have classes
     var className = getAttr(this[i], 'class');
-    var numClasses;
-    var setClass;
 
     if (!className) {
       setAttr(this[i], 'class', classNames.join(' ').trim());
     } else {
-      setClass = ' ' + className + ' ';
-      numClasses = classNames.length;
+      var setClass = ' ' + className + ' ';
 
       // Check if class already exists
-      for (var j = 0; j < numClasses; j++) {
+      for (var j = 0; j < classNames.length; j++) {
         var appendClass = classNames[j] + ' ';
         if (setClass.indexOf(' ' + appendClass) < 0) setClass += appendClass;
       }
@@ -544,10 +521,6 @@ exports.addClass = function (value) {
  * @see {@link http://api.jquery.com/removeClass/}
  */
 exports.removeClass = function (value) {
-  var classes;
-  var numClasses;
-  var removeAll;
-
   // Handle if value is a function
   if (typeof value === 'function') {
     return domEach(this, function (i, el) {
@@ -558,9 +531,9 @@ exports.removeClass = function (value) {
     });
   }
 
-  classes = splitNames(value);
-  numClasses = classes.length;
-  removeAll = arguments.length === 0;
+  var classes = splitNames(value);
+  var numClasses = classes.length;
+  var removeAll = arguments.length === 0;
 
   return domEach(this, function (i, el) {
     if (!isTag(el)) return;
@@ -570,11 +543,10 @@ exports.removeClass = function (value) {
       el.attribs.class = '';
     } else {
       var elClasses = splitNames(el.attribs.class);
-      var index;
-      var changed;
+      var changed = false;
 
       for (var j = 0; j < numClasses; j++) {
-        index = elClasses.indexOf(classes[j]);
+        var index = elClasses.indexOf(classes[j]);
 
         if (index >= 0) {
           elClasses.splice(index, 1);
@@ -629,19 +601,17 @@ exports.toggleClass = function (value, stateVal) {
   var numClasses = classNames.length;
   var state = typeof stateVal === 'boolean' ? (stateVal ? 1 : -1) : 0;
   var numElements = this.length;
-  var elementClasses;
-  var index;
 
   for (var i = 0; i < numElements; i++) {
     // If selected element isn't a tag, move on
     if (!isTag(this[i])) continue;
 
-    elementClasses = splitNames(this[i].attribs.class);
+    var elementClasses = splitNames(this[i].attribs.class);
 
     // Check if class already exists
     for (var j = 0; j < numClasses; j++) {
       // Check if the class name is currently defined
-      index = elementClasses.indexOf(classNames[j]);
+      var index = elementClasses.indexOf(classNames[j]);
 
       // Add if stateValue === true or we are toggling and there is no value
       if (state >= 0 && index < 0) {
diff --git a/lib/api/forms.js b/lib/api/forms.js
index 161a4320d9..3e1cd8bac7 100644
--- a/lib/api/forms.js
+++ b/lib/api/forms.js
@@ -38,8 +38,7 @@ exports.serialize = function () {
 exports.serializeArray = function () {
   // Resolve all form elements from either forms or collections of form elements
   var Cheerio = this.constructor;
-  return this.map(function () {
-    var elem = this;
+  return this.map(function (i, elem) {
     var $elem = Cheerio(elem);
     if (elem.name === 'form') {
       return $elem.find(submittableSelector).toArray();
diff --git a/lib/api/manipulation.js b/lib/api/manipulation.js
index d17f0dda1a..c9b349e561 100644
--- a/lib/api/manipulation.js
+++ b/lib/api/manipulation.js
@@ -42,26 +42,22 @@ exports._makeDomArray = function makeDomArray(elem, clone) {
   return clone ? cloneDom([elem]) : [elem];
 };
 
-var _insert = function (concatenator) {
+function _insert(concatenator) {
   return function () {
     var elems = slice.call(arguments);
     var lastIdx = this.length - 1;
 
     return domEach(this, function (i, el) {
-      var dom;
-      var domSrc;
+      var domSrc =
+        typeof elems[0] === 'function'
+          ? elems[0].call(el, i, html(el.children))
+          : elems;
 
-      if (typeof elems[0] === 'function') {
-        domSrc = elems[0].call(el, i, html(el.children));
-      } else {
-        domSrc = elems;
-      }
-
-      dom = this._makeDomArray(domSrc, i < lastIdx);
+      var dom = this._makeDomArray(domSrc, i < lastIdx);
       concatenator(dom, el.children, el);
     });
   };
-};
+}
 
 /*
  * Modify an array in-place, removing some number of elements and adding new
@@ -74,22 +70,17 @@ var _insert = function (concatenator) {
  *
  * @private
  */
-var uniqueSplice = function (array, spliceIdx, spliceCount, newElems, parent) {
+function uniqueSplice(array, spliceIdx, spliceCount, newElems, parent) {
   var spliceArgs = [spliceIdx, spliceCount].concat(newElems);
   var prev = array[spliceIdx - 1] || null;
   var next = array[spliceIdx + spliceCount] || null;
-  var idx;
-  var len;
-  var prevIdx;
-  var node;
-  var oldParent;
 
   // Before splicing in new elements, ensure they do not already appear in the
   // current array.
-  for (idx = 0, len = newElems.length; idx < len; ++idx) {
-    node = newElems[idx];
-    oldParent = node.parent;
-    prevIdx = oldParent && oldParent.children.indexOf(newElems[idx]);
+  for (var idx = 0; idx < newElems.length; ++idx) {
+    var node = newElems[idx];
+    var oldParent = node.parent;
+    var prevIdx = oldParent && oldParent.children.indexOf(newElems[idx]);
 
     if (oldParent && prevIdx > -1) {
       oldParent.children.splice(prevIdx, 1);
@@ -119,7 +110,7 @@ var uniqueSplice = function (array, spliceIdx, spliceCount, newElems, parent) {
     next.prev = newElems[newElems.length - 1];
   }
   return array.splice.apply(array, spliceArgs);
-};
+}
 
 /**
  * Insert every element in the set of matched elements to the end of the
@@ -241,9 +232,6 @@ function _wrap(insert) {
 
     for (var i = 0; i < this.length; i++) {
       var el = this[i];
-      var wrapperDom;
-      var elInsertLocation;
-      var j;
 
       if (wrapperFn) {
         wrapper = wrapperFn.call(el, i);
@@ -253,11 +241,11 @@ function _wrap(insert) {
         wrapper = lastParent.find(wrapper).clone();
       }
 
-      wrapperDom = this._makeDomArray(wrapper, i < lastIdx).slice(0, 1);
-      elInsertLocation = wrapperDom[0];
+      var wrapperDom = this._makeDomArray(wrapper, i < lastIdx).slice(0, 1);
+      var elInsertLocation = wrapperDom[0];
       // Find the deepest child. Only consider the first tag child of each node
       // (ignore text); stop if no children are found.
-      j = 0;
+      var j = 0;
 
       while (elInsertLocation && elInsertLocation.children) {
         if (j >= elInsertLocation.children.length) {
@@ -395,7 +383,7 @@ exports.after = function () {
   var elems = slice.call(arguments);
   var lastIdx = this.length - 1;
 
-  domEach(this, function (i, el) {
+  return domEach(this, function (i, el) {
     var parent = el.parent;
     if (!parent) {
       return;
@@ -403,24 +391,20 @@ exports.after = function () {
 
     var siblings = parent.children;
     var index = siblings.indexOf(el);
-    var domSrc;
-    var dom;
 
     // If not found, move on
     if (index < 0) return;
 
-    if (typeof elems[0] === 'function') {
-      domSrc = elems[0].call(el, i, html(el.children));
-    } else {
-      domSrc = elems;
-    }
-    dom = this._makeDomArray(domSrc, i < lastIdx);
+    var domSrc =
+      typeof elems[0] === 'function'
+        ? elems[0].call(el, i, html(el.children))
+        : elems;
+
+    var dom = this._makeDomArray(domSrc, i < lastIdx);
 
     // Add element after `this` element
     uniqueSplice(siblings, index + 1, 0, dom, parent);
   });
-
-  return this;
 };
 
 /**
@@ -494,7 +478,7 @@ exports.before = function () {
   var elems = slice.call(arguments);
   var lastIdx = this.length - 1;
 
-  domEach(this, function (i, el) {
+  return domEach(this, function (i, el) {
     var parent = el.parent;
     if (!parent) {
       return;
@@ -502,25 +486,20 @@ exports.before = function () {
 
     var siblings = parent.children;
     var index = siblings.indexOf(el);
-    var domSrc;
-    var dom;
 
     // If not found, move on
     if (index < 0) return;
 
-    if (typeof elems[0] === 'function') {
-      domSrc = elems[0].call(el, i, html(el.children));
-    } else {
-      domSrc = elems;
-    }
+    var domSrc =
+      typeof elems[0] === 'function'
+        ? elems[0].call(el, i, html(el.children))
+        : elems;
 
-    dom = this._makeDomArray(domSrc, i < lastIdx);
+    var dom = this._makeDomArray(domSrc, i < lastIdx);
 
     // Add element before `el` element
     uniqueSplice(siblings, index, 0, dom, parent);
   });
-
-  return this;
 };
 
 /**
@@ -592,10 +571,8 @@ exports.insertBefore = function (target) {
  * @see {@link http://api.jquery.com/remove/}
  */
 exports.remove = function (selector) {
-  var elems = this;
-
   // Filter if we have selector
-  if (selector) elems = elems.filter(selector);
+  var elems = selector ? this.filter(selector) : this;
 
   domEach(elems, function (i, el) {
     DomUtils.removeElement(el);
@@ -624,25 +601,22 @@ exports.remove = function (selector) {
  * @see {@link http://api.jquery.com/replaceWith/}
  */
 exports.replaceWith = function (content) {
-  var self = this;
-
-  domEach(this, function (i, el) {
+  return domEach(this, function (i, el) {
     var parent = el.parent;
     if (!parent) {
       return;
     }
 
     var siblings = parent.children;
-    var dom = self._makeDomArray(
+    var dom = this._makeDomArray(
       typeof content === 'function' ? content.call(el, i, el) : content
     );
-    var index;
 
     // In the case that `dom` contains nodes that already exist in other
     // structures, ensure those nodes are properly removed.
     updateDOM(dom, null);
 
-    index = siblings.indexOf(el);
+    var index = siblings.indexOf(el);
 
     // Completely remove old element
     uniqueSplice(siblings, index, 1, dom, parent);
@@ -651,8 +625,6 @@ exports.replaceWith = function (content) {
       el.parent = el.prev = el.next = null;
     }
   });
-
-  return this;
 };
 
 /**
@@ -667,14 +639,13 @@ exports.replaceWith = function (content) {
  * @see {@link http://api.jquery.com/empty/}
  */
 exports.empty = function () {
-  domEach(this, function (i, el) {
+  return domEach(this, function (i, el) {
     el.children.forEach(function (child) {
       child.next = child.prev = child.parent = null;
     });
 
     el.children.length = 0;
   });
-  return this;
 };
 
 /**
@@ -702,7 +673,7 @@ exports.html = function (str) {
 
   var opts = this.options;
 
-  domEach(this, function (i, el) {
+  return domEach(this, function (i, el) {
     el.children.forEach(function (child) {
       child.next = child.prev = child.parent = null;
     });
@@ -713,8 +684,6 @@ exports.html = function (str) {
 
     updateDOM(content, el);
   });
-
-  return this;
 };
 
 exports.toString = function () {
@@ -746,14 +715,13 @@ exports.text = function (str) {
     return text(this);
   } else if (typeof str === 'function') {
     // Function support
-    var self = this;
     return domEach(this, function (i, el) {
-      return exports.text.call(self._make(el), str.call(el, i, text([el])));
+      return exports.text.call(this._make(el), str.call(el, i, text([el])));
     });
   }
 
   // Append text node to each selected elements
-  domEach(this, function (i, el) {
+  return domEach(this, function (i, el) {
     el.children.forEach(function (child) {
       child.next = child.prev = child.parent = null;
     });
@@ -762,8 +730,6 @@ exports.text = function (str) {
 
     updateDOM(textNode, el);
   });
-
-  return this;
 };
 
 /**
diff --git a/lib/api/traversing.js b/lib/api/traversing.js
index 1b159d280b..e6933bacf8 100644
--- a/lib/api/traversing.js
+++ b/lib/api/traversing.js
@@ -27,34 +27,27 @@ var reSiblingSelector = /^\s*[~+]/;
  * @see {@link http://api.jquery.com/find/}
  */
 exports.find = function (selectorOrHaystack) {
-  var contains = this.constructor.contains;
-  var haystack;
-
-  if (selectorOrHaystack && typeof selectorOrHaystack !== 'string') {
-    if (selectorOrHaystack.cheerio) {
-      haystack = selectorOrHaystack.get();
-    } else {
-      haystack = [selectorOrHaystack];
-    }
+  if (!selectorOrHaystack) {
+    return this._make([]);
+  }
+
+  var context = this.toArray();
+
+  if (typeof selectorOrHaystack !== 'string') {
+    var contains = this.constructor.contains;
+    var haystack = selectorOrHaystack.cheerio
+      ? selectorOrHaystack.get()
+      : [selectorOrHaystack];
 
     return this._make(
       haystack.filter(function (elem) {
-        var idx;
-        var len;
-        for (idx = 0, len = this.length; idx < len; ++idx) {
-          if (contains(this[idx], elem)) {
-            return true;
-          }
-        }
-      }, this)
+        return context.some(function (node) {
+          return contains(node, elem);
+        });
+      })
     );
   }
 
-  if (!selectorOrHaystack) {
-    return this._make([]);
-  }
-
-  var context = this.toArray();
   var elems = reSiblingSelector.test(selectorOrHaystack)
     ? context
     : context.reduce(function (newElems, elem) {
@@ -253,7 +246,7 @@ exports.next = function (selector) {
   }
   var elems = [];
 
-  this.toArray().forEach(function (elem) {
+  domEach(this, function (idx, elem) {
     while ((elem = elem.next)) {
       if (isTag(elem)) {
         elems.push(elem);
@@ -288,7 +281,7 @@ exports.nextAll = function (selector) {
   }
   var elems = [];
 
-  this.toArray().forEach(function (elem) {
+  domEach(this, function (idx, elem) {
     while ((elem = elem.next)) {
       if (isTag(elem) && elems.indexOf(elem) === -1) {
         elems.push(elem);
@@ -331,7 +324,7 @@ exports.nextUntil = function (selector, filterSelector) {
     untilNode = selector;
   }
 
-  this.toArray().forEach(function (elem) {
+  domEach(this, function (idx, elem) {
     while ((elem = elem.next)) {
       if (
         (untilNode && elem !== untilNode) ||
@@ -371,7 +364,7 @@ exports.prev = function (selector) {
   }
   var elems = [];
 
-  this.toArray().forEach(function (elem) {
+  domEach(this, function (idx, elem) {
     while ((elem = elem.prev)) {
       if (isTag(elem)) {
         elems.push(elem);
@@ -406,7 +399,7 @@ exports.prevAll = function (selector) {
   }
   var elems = [];
 
-  this.toArray().forEach(function (elem) {
+  domEach(this, function (idx, elem) {
     while ((elem = elem.prev)) {
       if (isTag(elem) && elems.indexOf(elem) === -1) {
         elems.push(elem);
@@ -449,7 +442,7 @@ exports.prevUntil = function (selector, filterSelector) {
     untilNode = selector;
   }
 
-  this.toArray().forEach(function (elem) {
+  domEach(this, function (idx, elem) {
     while ((elem = elem.prev)) {
       if (
         (untilNode && elem !== untilNode) ||
@@ -690,16 +683,14 @@ exports.filter = function (match, container) {
 exports.not = function (match, container) {
   container = container || this;
   var elements = container.toArray ? container.toArray() : container;
-  var matches;
-  var filterFn;
 
   if (typeof match === 'string') {
-    matches = new Set(select.filter(match, elements, this.options));
+    var matches = new Set(select.filter(match, elements, this.options));
     elements = elements.filter(function (el) {
       return !matches.has(el);
     });
   } else {
-    filterFn = getFilterFn(match);
+    var filterFn = getFilterFn(match);
     elements = elements.filter(function (el, i) {
       return !filterFn(el, i);
     });
@@ -729,8 +720,8 @@ exports.not = function (match, container) {
  */
 exports.has = function (selectorOrHaystack) {
   var that = this;
-  return exports.filter.call(this, function () {
-    return that._make(this).find(selectorOrHaystack).length > 0;
+  return exports.filter.call(this, function (i, el) {
+    return that._make(el).find(selectorOrHaystack).length > 0;
   });
 };
 
diff --git a/lib/cheerio.js b/lib/cheerio.js
index 8e69a9b8ee..e84f59dd35 100644
--- a/lib/cheerio.js
+++ b/lib/cheerio.js
@@ -55,6 +55,11 @@ var Cheerio = (module.exports = function (selector, context, root, options) {
     this._root = Cheerio.call(this, root);
   }
 
+  // $(<html>)
+  if (typeof selector === 'string' && isHtml(selector)) {
+    selector = parse(selector, this.options, false).children;
+  }
+
   // $($)
   if (selector.cheerio) return selector;
 
@@ -70,11 +75,6 @@ var Cheerio = (module.exports = function (selector, context, root, options) {
     return this;
   }
 
-  // $(<html>)
-  if (typeof selector === 'string' && isHtml(selector)) {
-    return Cheerio.call(this, parse(selector, this.options, false).children);
-  }
-
   // If we don't have a context, maybe we have a root, from loading
   if (!context) {
     context = this._root;
@@ -85,7 +85,7 @@ var Cheerio = (module.exports = function (selector, context, root, options) {
       context = Cheerio.call(this, context);
     } else {
       // $('li', 'ul')
-      selector = [context, selector].join(' ');
+      selector = context + ' ' + selector;
       context = this._root;
     }
   } else if (!context.cheerio) {
@@ -134,20 +134,18 @@ Cheerio.prototype.toArray = function () {
 };
 
 // Support for (const element of $(...)) iteration:
-if (typeof Symbol !== 'undefined') {
-  Cheerio.prototype[Symbol.iterator] = Array.prototype[Symbol.iterator];
-}
+Cheerio.prototype[Symbol.iterator] = Array.prototype[Symbol.iterator];
 
 // Plug in the API
 api.forEach(function (mod) {
   Object.assign(Cheerio.prototype, mod);
 });
 
-var isNode = function (obj) {
+function isNode(obj) {
   return (
     obj.name ||
     obj.type === 'root' ||
     obj.type === 'text' ||
     obj.type === 'comment'
   );
-};
+}
diff --git a/lib/parse.js b/lib/parse.js
index 51ca038089..f909fd91cb 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -4,46 +4,39 @@
 var htmlparser = require('htmlparser2');
 var parse5 = require('parse5');
 var htmlparser2Adapter = require('parse5-htmlparser2-tree-adapter');
-var domhandler = require('domhandler');
 var DomUtils = htmlparser.DomUtils;
+var Document = require('domhandler').Document;
 
 /*
   Parser
 */
 exports = module.exports = function parse(content, options, isDocument) {
-  // options = options || $.fn.options;
-
-  var dom;
-
   if (typeof Buffer !== 'undefined' && Buffer.isBuffer(content)) {
     content = content.toString();
   }
 
   if (typeof content === 'string') {
-    var useHtmlParser2 = options.xmlMode || options._useHtmlParser2;
-
-    dom = useHtmlParser2
+    return options.xmlMode || options._useHtmlParser2
       ? htmlparser.parseDocument(content, options)
       : parseWithParse5(content, options, isDocument);
-  } else {
-    if (
-      typeof content === 'object' &&
-      content != null &&
-      content.type === 'root'
-    ) {
-      dom = content;
-    } else {
-      // Generic root element
-      var root = new domhandler.Document(content);
-
-      // Update the DOM using the root
-      exports.update(content, root);
+  }
 
-      dom = root;
-    }
+  if (
+    typeof content === 'object' &&
+    content != null &&
+    content.type === 'root'
+  ) {
+    // If `content` is already a root, just return it
+    return content;
   }
 
-  return dom;
+  // Add conent to new root element
+  var root = new Document(content);
+
+  // Update the DOM using the root
+  exports.update(content, root);
+
+  return root;
 };
 
 function parseWithParse5(content, options, isDocument) {
diff --git a/lib/static.js b/lib/static.js
index 1a8b40a7f2..2cf285ebb5 100644
--- a/lib/static.js
+++ b/lib/static.js
@@ -38,13 +38,13 @@ exports.load = function (content, options, isDocument) {
 
   var root = parse(content, options, isDocument);
 
-  var initialize = function (selector, context, r, opts) {
+  function initialize(selector, context, r, opts) {
     if (!(this instanceof initialize)) {
       return new initialize(selector, context, r, opts);
     }
     opts = Object.assign({}, options, opts);
     return Cheerio.call(this, selector, context, r || root, opts);
-  };
+  }
 
   // Ensure that selections created by the "loaded" `initialize` function are
   // true Cheerio instances.
@@ -125,8 +125,8 @@ exports.html = function (dom, options) {
     dom = undefined;
   }
 
-  // sometimes $.html() used without preloading html
-  // so fallback non existing options to the default ones
+  // Sometimes `$.html()` is used without preloading html,
+  // so fallback non-existing options to the default ones.
   options = Object.assign(
     {},
     defaultOptions,
@@ -151,7 +151,7 @@ exports.xml = function (dom) {
 /**
  * Render the document as text.
  *
- * @param {string|cheerio|node} [elems] - Elements to render.
+ * @param {cheerio|node} [elems] - Elements to render.
  */
 exports.text = function (elems) {
   if (!elems) {
@@ -160,10 +160,9 @@ exports.text = function (elems) {
 
   var ret = '';
   var len = elems.length;
-  var elem;
 
   for (var i = 0; i < len; i++) {
-    elem = elems[i];
+    var elem = elems[i];
     if (elem.type === 'text') ret += elem.data;
     else if (
       elem.children &&
@@ -190,8 +189,6 @@ exports.text = function (elems) {
  * @see {@link https://api.jquery.com/jQuery.parseHTML/}
  */
 exports.parseHTML = function (data, context, keepScripts) {
-  var parsed;
-
   if (!data || typeof data !== 'string') {
     return null;
   }
@@ -200,7 +197,7 @@ exports.parseHTML = function (data, context, keepScripts) {
     keepScripts = context;
   }
 
-  parsed = this.load(data, defaultOptions, false);
+  var parsed = this.load(data, defaultOptions, false);
   if (!keepScripts) {
     parsed('script').remove();
   }
diff --git a/test/api/deprecated.js b/test/api/deprecated.js
index dce84dfcbd..b1ec50a635 100644
--- a/test/api/deprecated.js
+++ b/test/api/deprecated.js
@@ -210,16 +210,16 @@ describe('deprecated APIs', function () {
      * is deprecated.
      *
      * In order to promote consistency with the jQuery library, users are
-     * encouraged to instead use the instance method of the same name. For
-     * example:
+     * encouraged to instead use the instance method of the same name.
      *
+     * @example
      *     var $ = cheerio.load('<h1>Hello, <span>world</span>.</h1>');
      *     $('h1').html(); // '<h1>Hello, <span>world</span>.'.
      *
-     * To render the markup of an entire document, invoke the `html` function
-     * exported by the Cheerio module with a "root" selection, e.g.
+     * @example <caption>To render the markup of an entire document, invoke the `html` function
+     * exported by the Cheerio module with a "root" selection.</caption>
      *
-     *     Cheerio.html($.root()); // '<html><head></head><body><h1>Hello, <span>world</span>.</h1></body></html>'.
+     *     cheerio.html($.root()); // '<html><head></head><body><h1>Hello, <span>world</span>.</h1></body></html>'.
      */
     describe('.html - deprecated API', function () {
       it('() : of empty cheerio object should return null', function () {
diff --git a/test/api/manipulation.js b/test/api/manipulation.js
index 2bf629635b..ca239723b0 100644
--- a/test/api/manipulation.js
+++ b/test/api/manipulation.js
@@ -73,11 +73,9 @@ describe('$(...)', function () {
     });
 
     it('(selector) : wraps the content with a copy of the first matched element', function () {
-      var $oranges;
-
       $('.apple').wrap('.orange, .pear');
 
-      $oranges = $('.orange');
+      var $oranges = $('.orange');
       expect($('.pear')).to.have.length(1);
       expect($oranges).to.have.length(2);
       expect($oranges.eq(0).parent()[0]).to.be($fruits[0]);
@@ -209,9 +207,8 @@ describe('$(...)', function () {
     });
 
     it("(selector) : should wrap the html of the element with the selector's first match", function () {
-      var $oranges;
       $('.apple').wrapInner('.orange, .pear');
-      $oranges = $('.orange');
+      var $oranges = $('.orange');
       expect($('.pear')).to.have.length(1);
       expect($oranges).to.have.length(2);
       expect($oranges.eq(0).parent()[0]).to.be($('.apple')[0]);
@@ -345,11 +342,10 @@ describe('$(...)', function () {
 
     it('(existing Node) : should remove node from previous location', function () {
       var apple = $fruits.children()[0];
-      var $children;
 
       expect($fruits.children()).to.have.length(3);
       $fruits.append(apple);
-      $children = $fruits.children();
+      var $children = $fruits.children();
 
       expect($children).to.have.length(3);
       expect($children[0]).to.not.equal(apple);
@@ -358,12 +354,11 @@ describe('$(...)', function () {
 
     it('(existing Node) : should remove existing node from previous location', function () {
       var apple = $fruits.children()[0];
-      var $children;
       var $dest = $('<div></div>');
 
       expect($fruits.children()).to.have.length(3);
       $dest.append(apple);
-      $children = $fruits.children();
+      var $children = $fruits.children();
 
       expect($children).to.have.length(2);
       expect($children[0]).to.not.equal(apple);
@@ -380,11 +375,10 @@ describe('$(...)', function () {
 
     it('(existing Node) : should clone all but the last occurrence', function () {
       var $originalApple = $('.apple');
-      var $apples;
 
       $('.orange, .pear').append($originalApple);
 
-      $apples = $('.apple');
+      var $apples = $('.apple');
       expect($apples).to.have.length(2);
       expect($apples.eq(0).parent()[0]).to.be($('.orange')[0]);
       expect($apples.eq(1).parent()[0]).to.be($('.pear')[0]);
@@ -436,17 +430,14 @@ describe('$(...)', function () {
 
     it('(fn) : should add returned string as last child', function () {
       $fruits = $fruits.children();
-      var $apple;
-      var $orange;
-      var $pear;
 
       $fruits.append(function () {
         return '<div class="first">';
       });
 
-      $apple = $fruits.eq(0);
-      $orange = $fruits.eq(1);
-      $pear = $fruits.eq(2);
+      var $apple = $fruits.eq(0);
+      var $orange = $fruits.eq(1);
+      var $pear = $fruits.eq(2);
 
       expect($apple.find('.first')[0]).to.equal($apple.contents()[1]);
       expect($orange.find('.first')[0]).to.equal($orange.contents()[1]);
@@ -454,18 +445,15 @@ describe('$(...)', function () {
     });
 
     it('(fn) : should add returned Cheerio object as last child', function () {
-      var $apple;
-      var $orange;
-      var $pear;
       $fruits = $fruits.children();
 
       $fruits.append(function () {
         return $('<div class="second">');
       });
 
-      $apple = $fruits.eq(0);
-      $orange = $fruits.eq(1);
-      $pear = $fruits.eq(2);
+      var $apple = $fruits.eq(0);
+      var $orange = $fruits.eq(1);
+      var $pear = $fruits.eq(2);
 
       expect($apple.find('.second')[0]).to.equal($apple.contents()[1]);
       expect($orange.find('.second')[0]).to.equal($orange.contents()[1]);
@@ -473,18 +461,15 @@ describe('$(...)', function () {
     });
 
     it('(fn) : should add returned Node as last child', function () {
-      var $apple;
-      var $orange;
-      var $pear;
       $fruits = $fruits.children();
 
       $fruits.append(function () {
         return $('<div class="third">')[0];
       });
 
-      $apple = $fruits.eq(0);
-      $orange = $fruits.eq(1);
-      $pear = $fruits.eq(2);
+      var $apple = $fruits.eq(0);
+      var $orange = $fruits.eq(1);
+      var $pear = $fruits.eq(2);
 
       expect($apple.find('.third')[0]).to.equal($apple.contents()[1]);
       expect($orange.find('.third')[0]).to.equal($orange.contents()[1]);
@@ -551,11 +536,10 @@ describe('$(...)', function () {
 
     it('(existing Node) : should remove existing nodes from previous locations', function () {
       var pear = $fruits.children()[2];
-      var $children;
 
       expect($fruits.children()).to.have.length(3);
       $fruits.prepend(pear);
-      $children = $fruits.children();
+      var $children = $fruits.children();
 
       expect($children).to.have.length(3);
       expect($children[2]).to.not.equal(pear);
@@ -570,11 +554,10 @@ describe('$(...)', function () {
 
     it('(existing Node) : should clone all but the last occurrence', function () {
       var $originalApple = $('.apple');
-      var $apples;
 
       $('.orange, .pear').prepend($originalApple);
 
-      $apples = $('.apple');
+      var $apples = $('.apple');
       expect($apples).to.have.length(2);
       expect($apples.eq(0).parent()[0]).to.be($('.orange')[0]);
       expect($apples.eq(1).parent()[0]).to.be($('.pear')[0]);
@@ -625,18 +608,15 @@ describe('$(...)', function () {
     });
 
     it('(fn) : should add returned string as first child', function () {
-      var $apple;
-      var $orange;
-      var $pear;
       $fruits = $fruits.children();
 
       $fruits.prepend(function () {
         return '<div class="first">';
       });
 
-      $apple = $fruits.eq(0);
-      $orange = $fruits.eq(1);
-      $pear = $fruits.eq(2);
+      var $apple = $fruits.eq(0);
+      var $orange = $fruits.eq(1);
+      var $pear = $fruits.eq(2);
 
       expect($apple.find('.first')[0]).to.equal($apple.contents()[0]);
       expect($orange.find('.first')[0]).to.equal($orange.contents()[0]);
@@ -644,18 +624,15 @@ describe('$(...)', function () {
     });
 
     it('(fn) : should add returned Cheerio object as first child', function () {
-      var $apple;
-      var $orange;
-      var $pear;
       $fruits = $fruits.children();
 
       $fruits.prepend(function () {
         return $('<div class="second">');
       });
 
-      $apple = $fruits.eq(0);
-      $orange = $fruits.eq(1);
-      $pear = $fruits.eq(2);
+      var $apple = $fruits.eq(0);
+      var $orange = $fruits.eq(1);
+      var $pear = $fruits.eq(2);
 
       expect($apple.find('.second')[0]).to.equal($apple.contents()[0]);
       expect($orange.find('.second')[0]).to.equal($orange.contents()[0]);
@@ -663,18 +640,15 @@ describe('$(...)', function () {
     });
 
     it('(fn) : should add returned Node as first child', function () {
-      var $apple;
-      var $orange;
-      var $pear;
       $fruits = $fruits.children();
 
       $fruits.prepend(function () {
         return $('<div class="third">')[0];
       });
 
-      $apple = $fruits.eq(0);
-      $orange = $fruits.eq(1);
-      $pear = $fruits.eq(2);
+      var $apple = $fruits.eq(0);
+      var $orange = $fruits.eq(1);
+      var $pear = $fruits.eq(2);
 
       expect($apple.find('.third')[0]).to.equal($apple.contents()[0]);
       expect($orange.find('.third')[0]).to.equal($orange.contents()[0]);
@@ -784,11 +758,10 @@ describe('$(...)', function () {
 
     it('(existing Node) : should remove existing nodes from previous locations', function () {
       var pear = $fruits.children()[2];
-      var $children;
 
       $('.apple').after(pear);
 
-      $children = $fruits.children();
+      var $children = $fruits.children();
       expect($children).to.have.length(3);
       expect($children[1]).to.be(pear);
     });
@@ -1052,11 +1025,10 @@ describe('$(...)', function () {
 
     it('(existing Node) : should remove existing nodes from previous locations', function () {
       var pear = $fruits.children()[2];
-      var $children;
 
       $('.apple').before(pear);
 
-      $children = $fruits.children();
+      var $children = $fruits.children();
       expect($children).to.have.length(3);
       expect($children[0]).to.be(pear);
     });
@@ -1392,13 +1364,13 @@ describe('$(...)', function () {
     });
 
     it('(self) : should be replaced after replacing it with itself', function () {
-      var $ = cheerio.load('<a>foo</a>', null, false);
+      var $a = cheerio.load('<a>foo</a>', null, false);
       var replacement = '<a>bar</a>';
-      $('a').replaceWith(function (i, el) {
+      $a('a').replaceWith(function (i, el) {
         return el;
       });
-      $('a').replaceWith(replacement);
-      expect($.html()).to.be.equal(replacement);
+      $a('a').replaceWith(replacement);
+      expect($a.html()).to.be.equal(replacement);
     });
 
     it('(str) : should accept strings', function () {
@@ -1618,10 +1590,9 @@ describe('$(...)', function () {
 
     it('(text) : should create a Node with the DOM level 1 API', function () {
       var $apple = $('.apple');
-      var textNode;
 
       $apple.text('anything');
-      textNode = $apple[0].childNodes[0];
+      var textNode = $apple[0].childNodes[0];
 
       expect(textNode.parentNode).to.be($apple[0]);
       expect(textNode.nodeType).to.be(3);
diff --git a/test/api/utils.js b/test/api/utils.js
index 8732f8a54c..3893268885 100644
--- a/test/api/utils.js
+++ b/test/api/utils.js
@@ -230,10 +230,10 @@ describe('cheerio', function () {
     });
 
     it('(text) : should return an array that is not effected by DOM manipulation methods', function () {
-      var $ = cheerio.load('<div>');
-      var elems = $.parseHTML('<b></b><i></i>');
+      var $div = cheerio.load('<div>');
+      var elems = $div.parseHTML('<b></b><i></i>');
 
-      $('div').append(elems);
+      $div('div').append(elems);
 
       expect(elems).to.have.length(2);
     });
diff --git a/test/cheerio.js b/test/cheerio.js
index 865296b4c8..7217ea8fd4 100644
--- a/test/cheerio.js
+++ b/test/cheerio.js
@@ -54,7 +54,7 @@ describe('cheerio', function () {
     expect($script[0].childNodes).to.be.empty();
   });
 
-  var testAppleSelect = function ($apple) {
+  function testAppleSelect($apple) {
     expect($apple).to.have.length(1);
     $apple = $apple[0];
     expect($apple.parentNode.tagName).to.equal('ul');
@@ -62,7 +62,7 @@ describe('cheerio', function () {
     expect($apple.next.attribs['class']).to.equal('orange');
     expect($apple.childNodes).to.have.length(1);
     expect($apple.childNodes[0].data).to.equal('Apple');
-  };
+  }
 
   it('should be able to select .apple with only a context', function () {
     var $apple = cheerio('.apple', fruits);
@@ -323,7 +323,6 @@ describe('cheerio', function () {
     describe('prototype extensions', function () {
       it('should honor extensions defined on `prototype` property', function () {
         var $ = cheerio.load('<div>');
-        var $div;
         $.prototype.myPlugin = function () {
           return {
             context: this,
@@ -331,7 +330,7 @@ describe('cheerio', function () {
           };
         };
 
-        $div = $('div');
+        var $div = $('div');
 
         expect($div.myPlugin).to.be.a('function');
         expect($div.myPlugin().context).to.be($div);
@@ -344,7 +343,6 @@ describe('cheerio', function () {
 
       it('should honor extensions defined on `fn` property', function () {
         var $ = cheerio.load('<div>');
-        var $div;
         $.fn.myPlugin = function () {
           return {
             context: this,
@@ -352,7 +350,7 @@ describe('cheerio', function () {
           };
         };
 
-        $div = $('div');
+        var $div = $('div');
 
         expect($div.myPlugin).to.be.a('function');
         expect($div.myPlugin().context).to.be($div);
diff --git a/test/xml.js b/test/xml.js
index e26ea8fb3f..c9d7ddd089 100644
--- a/test/xml.js
+++ b/test/xml.js
@@ -1,16 +1,16 @@
 var expect = require('expect.js');
 var cheerio = require('..');
 
-var xml = function (str, options) {
+function xml(str, options) {
   options = Object.assign({ xml: true }, options);
   var $ = cheerio.load(str, options);
   return $.xml();
-};
+}
 
-var dom = function (str, options) {
+function dom(str, options) {
   var $ = cheerio.load('', options);
   return $(str).html();
-};
+}
 
 describe('render', function () {
   describe('(xml)', function () {
diff --git a/types/index.d.ts b/types/index.d.ts
index 77ac1c2c08..e55f5ab8f7 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -267,7 +267,7 @@ declare namespace cheerio {
     version: string;
     load(
       html: string | { toString(): string },
-      options?: CheerioParserOptions|null,
+      options?: CheerioParserOptions | null,
       isDocument?: boolean
     ): Root;
     load(element: Element, options?: CheerioParserOptions): Root;