diff --git a/lib/style.test.js b/lib/style.test.js
index 97c0900b..9171ffe1 100644
--- a/lib/style.test.js
+++ b/lib/style.test.js
@@ -2,6 +2,7 @@
 
 const { expect } = require('chai');
 const { computeStyle } = require('./style.js');
+const { querySelector } = require('./xast.js');
 const svg2js = require('./svgo/svg2js.js');
 
 describe('computeStyle', () => {
@@ -30,24 +31,24 @@ describe('computeStyle', () => {
         </style>
       </svg>
     `);
-    expect(computeStyle(root.querySelector('#class'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#class'))).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'red' },
     });
-    expect(computeStyle(root.querySelector('#two-classes'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#two-classes'))).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'green' },
       stroke: { type: 'static', inherited: false, value: 'black' },
     });
-    expect(computeStyle(root.querySelector('#attribute'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#attribute'))).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'purple' },
     });
-    expect(computeStyle(root.querySelector('#inline-style'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#inline-style'))).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'grey' },
     });
-    expect(computeStyle(root.querySelector('#inheritance'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#inheritance'))).to.deep.equal({
       fill: { type: 'static', inherited: true, value: 'yellow' },
     });
     expect(
-      computeStyle(root.querySelector('#nested-inheritance'))
+      computeStyle(querySelector(root, '#nested-inheritance'))
     ).to.deep.equal({
       fill: { type: 'static', inherited: true, value: 'blue' },
     });
@@ -69,23 +70,23 @@ describe('computeStyle', () => {
         </g>
       </svg>
     `);
-    expect(computeStyle(root.querySelector('#complex-selector'))).to.deep.equal(
-      {
-        fill: { type: 'static', inherited: false, value: 'red' },
-      }
-    );
     expect(
-      computeStyle(root.querySelector('#attribute-over-inheritance'))
+      computeStyle(querySelector(root, '#complex-selector'))
+    ).to.deep.equal({
+      fill: { type: 'static', inherited: false, value: 'red' },
+    });
+    expect(
+      computeStyle(querySelector(root, '#attribute-over-inheritance'))
     ).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'orange' },
     });
     expect(
-      computeStyle(root.querySelector('#style-rule-over-attribute'))
+      computeStyle(querySelector(root, '#style-rule-over-attribute'))
     ).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'blue' },
     });
     expect(
-      computeStyle(root.querySelector('#inline-style-over-style-rule'))
+      computeStyle(querySelector(root, '#inline-style-over-style-rule'))
     ).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'purple' },
     });
@@ -103,18 +104,18 @@ describe('computeStyle', () => {
         <rect id="inline-style-over-style-rule" style="fill: purple !important;" class="b" />
       </svg>
     `);
-    expect(computeStyle(root.querySelector('#complex-selector'))).to.deep.equal(
-      {
-        fill: { type: 'static', inherited: false, value: 'green' },
-      }
-    );
     expect(
-      computeStyle(root.querySelector('#style-rule-over-inline-style'))
+      computeStyle(querySelector(root, '#complex-selector'))
     ).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'green' },
     });
     expect(
-      computeStyle(root.querySelector('#inline-style-over-style-rule'))
+      computeStyle(querySelector(root, '#style-rule-over-inline-style'))
+    ).to.deep.equal({
+      fill: { type: 'static', inherited: false, value: 'green' },
+    });
+    expect(
+      computeStyle(querySelector(root, '#inline-style-over-style-rule'))
     ).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'purple' },
     });
@@ -140,21 +141,21 @@ describe('computeStyle', () => {
         <rect id="static" class="c" style="fill: black" />
       </svg>
     `);
-    expect(computeStyle(root.querySelector('#media-query'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#media-query'))).to.deep.equal({
       fill: { type: 'dynamic', inherited: false },
     });
-    expect(computeStyle(root.querySelector('#hover'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#hover'))).to.deep.equal({
       fill: { type: 'dynamic', inherited: false },
     });
-    expect(computeStyle(root.querySelector('#inherited'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#inherited'))).to.deep.equal({
       fill: { type: 'dynamic', inherited: true },
     });
     expect(
-      computeStyle(root.querySelector('#inherited-overriden'))
+      computeStyle(querySelector(root, '#inherited-overriden'))
     ).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'blue' },
     });
-    expect(computeStyle(root.querySelector('#static'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#static'))).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'black' },
     });
   });
@@ -176,13 +177,13 @@ describe('computeStyle', () => {
         <rect id="static" class="c" />
       </svg>
     `);
-    expect(computeStyle(root.querySelector('#media-query'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#media-query'))).to.deep.equal({
       fill: { type: 'dynamic', inherited: false },
     });
-    expect(computeStyle(root.querySelector('#kinda-static'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#kinda-static'))).to.deep.equal({
       fill: { type: 'dynamic', inherited: false },
     });
-    expect(computeStyle(root.querySelector('#static'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#static'))).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'blue' },
     });
   });
@@ -204,13 +205,15 @@ describe('computeStyle', () => {
         <rect id="invalid-type" class="c" />
       </svg>
     `);
-    expect(computeStyle(root.querySelector('#valid-type'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#valid-type'))).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'red' },
     });
-    expect(computeStyle(root.querySelector('#empty-type'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#empty-type'))).to.deep.equal({
       fill: { type: 'static', inherited: false, value: 'green' },
     });
-    expect(computeStyle(root.querySelector('#invalid-type'))).to.deep.equal({});
+    expect(computeStyle(querySelector(root, '#invalid-type'))).to.deep.equal(
+      {}
+    );
   });
 
   it('ignores keyframes atrule', () => {
@@ -235,7 +238,7 @@ describe('computeStyle', () => {
         <rect id="element" class="a" />
       </svg>
     `);
-    expect(computeStyle(root.querySelector('#element'))).to.deep.equal({
+    expect(computeStyle(querySelector(root, '#element'))).to.deep.equal({
       animation: {
         type: 'static',
         inherited: false,
diff --git a/lib/xast.js b/lib/xast.js
new file mode 100644
index 00000000..8a8118bc
--- /dev/null
+++ b/lib/xast.js
@@ -0,0 +1,53 @@
+'use strict';
+
+const { selectAll, selectOne, is } = require('css-select');
+const xastAdaptor = require('./svgo/css-select-adapter.js');
+
+const cssSelectOptions = {
+  xmlMode: true,
+  adapter: xastAdaptor,
+};
+
+const querySelectorAll = (node, selector) => {
+  return selectAll(selector, node, cssSelectOptions);
+};
+exports.querySelectorAll = querySelectorAll;
+
+const querySelector = (node, selector) => {
+  return selectOne(selector, node, cssSelectOptions);
+};
+exports.querySelector = querySelector;
+
+const matches = (node, selector) => {
+  return is(node, selector, cssSelectOptions);
+};
+exports.matches = matches;
+
+const closestByName = (node, name) => {
+  let currentNode = node;
+  while (currentNode) {
+    if (currentNode.type === 'element' && currentNode.name === name) {
+      return currentNode;
+    }
+    currentNode = currentNode.parentNode;
+  }
+  return null;
+};
+exports.closestByName = closestByName;
+
+const traverseBreak = Symbol();
+exports.traverseBreak = traverseBreak;
+
+const traverse = (node, fn) => {
+  if (fn(node) === traverseBreak) {
+    return traverseBreak;
+  }
+  if (node.type === 'root' || node.type === 'element') {
+    for (const child of node.children) {
+      if (traverse(child, fn) === traverseBreak) {
+        return traverseBreak;
+      }
+    }
+  }
+};
+exports.traverse = traverse;
diff --git a/plugins/cleanupEnableBackground.js b/plugins/cleanupEnableBackground.js
index 5ef55193..3abae8bb 100644
--- a/plugins/cleanupEnableBackground.js
+++ b/plugins/cleanupEnableBackground.js
@@ -1,5 +1,7 @@
 'use strict';
 
+const { traverse } = require('../lib/xast.js');
+
 exports.type = 'full';
 
 exports.active = true;
@@ -17,72 +19,55 @@ exports.description =
  *             ⬇
  * <svg width="100" height="50">
  *
- * @param {Object} item current iteration item
+ * @param {Object} root current iteration item
  * @return {Boolean} if false, item will be filtered out
  *
  * @author Kir Belevich
  */
-exports.fn = function (data) {
-  var regEnableBackground = /^new\s0\s0\s([-+]?\d*\.?\d+([eE][-+]?\d+)?)\s([-+]?\d*\.?\d+([eE][-+]?\d+)?)$/,
-    hasFilter = false,
-    elems = ['svg', 'mask', 'pattern'];
+exports.fn = function (root) {
+  const regEnableBackground = /^new\s0\s0\s([-+]?\d*\.?\d+([eE][-+]?\d+)?)\s([-+]?\d*\.?\d+([eE][-+]?\d+)?)$/;
+  let hasFilter = false;
+  const elems = ['svg', 'mask', 'pattern'];
 
-  function checkEnableBackground(item) {
-    if (
-      item.isElem(elems) &&
-      item.attributes['enable-background'] != null &&
-      item.attributes.width != null &&
-      item.attributes.height != null
-    ) {
-      var match = item.attributes['enable-background'].match(
-        regEnableBackground
-      );
+  traverse(root, (node) => {
+    if (node.type === 'element') {
+      if (
+        elems.includes(node.name) &&
+        node.attributes['enable-background'] != null &&
+        node.attributes.width != null &&
+        node.attributes.height != null
+      ) {
+        const match = node.attributes['enable-background'].match(
+          regEnableBackground
+        );
 
-      if (match) {
-        if (
-          item.attributes.width === match[1] &&
-          item.attributes.height === match[3]
-        ) {
-          if (item.isElem('svg')) {
-            delete item.attributes['enable-background'];
-          } else {
-            item.attributes['enable-background'] = 'new';
+        if (match) {
+          if (
+            node.attributes.width === match[1] &&
+            node.attributes.height === match[3]
+          ) {
+            if (node.name === 'svg') {
+              delete node.attributes['enable-background'];
+            } else {
+              node.attributes['enable-background'] = 'new';
+            }
           }
         }
       }
-    }
-  }
-
-  function checkForFilter(item) {
-    if (item.isElem('filter')) {
-      hasFilter = true;
-    }
-  }
-
-  function monkeys(items, fn) {
-    items.children.forEach(function (item) {
-      fn(item);
-
-      if (item.children) {
-        monkeys(item, fn);
+      if (node.name === 'filter') {
+        hasFilter = true;
       }
-    });
-    return items;
-  }
-
-  var firstStep = monkeys(data, function (item) {
-    checkEnableBackground(item);
-    if (!hasFilter) {
-      checkForFilter(item);
     }
   });
 
-  return hasFilter
-    ? firstStep
-    : monkeys(firstStep, (item) => {
-        if (item.type === 'element') {
-          //we don't need 'enable-background' if we have no filters
-          delete item.attributes['enable-background'];
-        }
-      });
+  if (hasFilter === false) {
+    traverse(root, (node) => {
+      if (node.type === 'element') {
+        //we don't need 'enable-background' if we have no filters
+        delete node.attributes['enable-background'];
+      }
+    });
+  }
+
+  return root;
 };
diff --git a/plugins/cleanupIDs.js b/plugins/cleanupIDs.js
index 62d382a2..08c99400 100644
--- a/plugins/cleanupIDs.js
+++ b/plugins/cleanupIDs.js
@@ -1,5 +1,6 @@
 'use strict';
 
+const { traverse, traverseBreak } = require('../lib/xast.js');
 const { parseName } = require('../lib/svgo/tools.js');
 
 exports.type = 'full';
@@ -87,7 +88,7 @@ var referencesProps = new Set(require('./_collections').referencesProps),
  *
  * @author Kir Belevich
  */
-exports.fn = function (data, params) {
+exports.fn = function (root, params) {
   var currentID,
     currentIDstring,
     IDs = new Map(),
@@ -110,88 +111,73 @@ exports.fn = function (data, params) {
     idValuePrefix = '#',
     idValuePostfix = '.';
 
-  /**
-   * Bananas!
-   *
-   * @param {Array} items input items
-   * @return {Array} output items
-   */
-  function monkeys(items) {
-    for (const item of items.children) {
-      if (hasStyleOrScript === true) {
-        break;
+  traverse(root, (node) => {
+    if (hasStyleOrScript === true) {
+      return traverseBreak;
+    }
+
+    // quit if <style> or <script> present ('force' param prevents quitting)
+    if (!params.force) {
+      if (node.isElem(styleOrScript) && node.children.length !== 0) {
+        hasStyleOrScript = true;
+        return;
       }
 
-      // quit if <style> or <script> present ('force' param prevents quitting)
-      if (!params.force) {
-        if (item.isElem(styleOrScript) && item.children.length !== 0) {
-          hasStyleOrScript = true;
-          continue;
-        }
-
-        // Don't remove IDs if the whole SVG consists only of defs.
-        if (item.isElem('svg')) {
-          var hasDefsOnly = true;
-
-          for (var j = 0; j < item.children.length; j++) {
-            if (!item.children[j].isElem('defs')) {
-              hasDefsOnly = false;
-              break;
-            }
-          }
-          if (hasDefsOnly) {
+      // Don't remove IDs if the whole SVG consists only of defs.
+      if (node.type === 'element' && node.name === 'svg') {
+        let hasDefsOnly = true;
+        for (const child of node.children) {
+          if (child.type !== 'element' || child.name !== 'defs') {
+            hasDefsOnly = false;
             break;
           }
         }
+        if (hasDefsOnly) {
+          return traverseBreak;
+        }
       }
-      // …and don't remove any ID if yes
-      if (item.type === 'element') {
-        for (const [name, value] of Object.entries(item.attributes)) {
-          let key;
-          let match;
+    }
 
-          // save IDs
-          if (name === 'id') {
-            key = value;
-            if (IDs.has(key)) {
-              delete item.attributes.id; // remove repeated id
-            } else {
-              IDs.set(key, item);
-            }
+    // …and don't remove any ID if yes
+    if (node.type === 'element') {
+      for (const [name, value] of Object.entries(node.attributes)) {
+        let key;
+        let match;
+
+        // save IDs
+        if (name === 'id') {
+          key = value;
+          if (IDs.has(key)) {
+            delete node.attributes.id; // remove repeated id
           } else {
-            // save references
-            const { local } = parseName(name);
-            if (
-              referencesProps.has(name) &&
-              (match = value.match(regReferencesUrl))
-            ) {
-              key = match[2]; // url() reference
-            } else if (
-              (local === 'href' && (match = value.match(regReferencesHref))) ||
-              (name === 'begin' && (match = value.match(regReferencesBegin)))
-            ) {
-              key = match[1]; // href reference
-            }
-            if (key) {
-              const refs = referencesIDs.get(key) || [];
-              refs.push({ element: item, name, value });
-              referencesIDs.set(key, refs);
-            }
+            IDs.set(key, node);
+          }
+        } else {
+          // save references
+          const { local } = parseName(name);
+          if (
+            referencesProps.has(name) &&
+            (match = value.match(regReferencesUrl))
+          ) {
+            key = match[2]; // url() reference
+          } else if (
+            (local === 'href' && (match = value.match(regReferencesHref))) ||
+            (name === 'begin' && (match = value.match(regReferencesBegin)))
+          ) {
+            key = match[1]; // href reference
+          }
+          if (key) {
+            const refs = referencesIDs.get(key) || [];
+            refs.push({ element: node, name, value });
+            referencesIDs.set(key, refs);
           }
         }
       }
-      // go deeper
-      if (item.type === 'root' || item.type === 'element') {
-        monkeys(item);
-      }
     }
-    return items;
-  }
-
-  data = monkeys(data);
+  });
 
   if (hasStyleOrScript) {
-    return data;
+    return root;
   }
 
   const idPreserved = (id) =>
@@ -234,7 +220,7 @@ exports.fn = function (data, params) {
       }
     }
   }
-  return data;
+  return root;
 };
 
 /**
diff --git a/plugins/inlineStyles.js b/plugins/inlineStyles.js
index 1be26575..bacf0b61 100644
--- a/plugins/inlineStyles.js
+++ b/plugins/inlineStyles.js
@@ -1,5 +1,9 @@
 'use strict';
 
+const csstree = require('css-tree');
+const { querySelectorAll, closestByName } = require('../lib/xast.js');
+const cssTools = require('../lib/css-tools');
+
 exports.type = 'full';
 
 exports.active = true;
@@ -13,9 +17,6 @@ exports.params = {
 
 exports.description = 'inline styles (additional options)';
 
-var csstree = require('css-tree'),
-  cssTools = require('../lib/css-tools');
-
 /**
  * Moves + merges styles from style elements to element styles
  *
@@ -35,18 +36,18 @@ var csstree = require('css-tree'),
  *     what pseudo-classes/-elements to be used
  *     empty string element for all non-pseudo-classes and/or -elements
  *
- * @param {Object} document document element
+ * @param {Object} root document element
  * @param {Object} opts plugin params
  *
  * @author strarsis <strarsis@gmail.com>
  */
-exports.fn = function (document, opts) {
+exports.fn = function (root, opts) {
   // collect <style/>s
-  var styleEls = document.querySelectorAll('style');
+  var styleEls = querySelectorAll(root, 'style');
 
   //no <styles/>s, nothing to do
-  if (styleEls === null) {
-    return document;
+  if (styleEls.length === 0) {
+    return root;
   }
 
   var styles = [],
@@ -62,7 +63,10 @@ exports.fn = function (document, opts) {
       continue;
     }
     // skip empty <style/>s or <foreignObject> content.
-    if (styleEl.children.length === 0 || styleEl.closestElem('foreignObject')) {
+    if (
+      styleEl.children.length === 0 ||
+      closestByName(styleEl, 'foreignObject')
+    ) {
       continue;
     }
 
@@ -108,13 +112,13 @@ exports.fn = function (document, opts) {
       selectedEls = null;
 
     try {
-      selectedEls = document.querySelectorAll(selectorStr);
+      selectedEls = querySelectorAll(root, selectorStr);
     } catch (selectError) {
       // console.warn('Warning: Syntax error when trying to select \n\n' + selectorStr + '\n\n, skipped. Error details: ' + selectError);
       continue;
     }
 
-    if (selectedEls === null) {
+    if (selectedEls.length === 0) {
       // nothing selected
       continue;
     }
@@ -181,7 +185,7 @@ exports.fn = function (document, opts) {
   }
 
   if (!opts.removeMatchedSelectors) {
-    return document; // no further processing required
+    return root; // no further processing required
   }
 
   // clean up matched class + ID attribute values
@@ -269,5 +273,5 @@ exports.fn = function (document, opts) {
     cssTools.setCssStr(style.styleEl, csstree.generate(style.cssAst));
   }
 
-  return document;
+  return root;
 };
diff --git a/plugins/minifyStyles.js b/plugins/minifyStyles.js
index b4cc2be9..a3aa5884 100755
--- a/plugins/minifyStyles.js
+++ b/plugins/minifyStyles.js
@@ -1,5 +1,8 @@
 'use strict';
 
+const csso = require('csso');
+const { traverse } = require('../lib/xast.js');
+
 exports.type = 'full';
 
 exports.active = true;
@@ -19,8 +22,6 @@ exports.params = {
   },
 };
 
-var csso = require('csso');
-
 /**
  * Minifies styles (<style> element + style attribute) using CSSO
  *
@@ -73,26 +74,17 @@ function cloneObject(obj) {
 }
 
 function findStyleElems(ast) {
-  function walk(items, styles) {
-    for (var i = 0; i < items.children.length; i++) {
-      var item = items.children[i];
-
-      // go deeper
-      if (item.children) {
-        walk(item, styles);
-      }
-
-      if (item.isElem('style') && item.children.length !== 0) {
-        styles.push(item);
-      } else if (item.type === 'element' && item.attributes.style != null) {
-        styles.push(item);
+  const nodesWithStyles = [];
+  traverse(ast, (node) => {
+    if (node.type === 'element') {
+      if (node.name === 'style' && node.children.length !== 0) {
+        nodesWithStyles.push(node);
+      } else if (node.attributes.style != null) {
+        nodesWithStyles.push(node);
       }
     }
-
-    return styles;
-  }
-
-  return walk(ast, []);
+  });
+  return nodesWithStyles;
 }
 
 function shouldFilter(options, name) {
@@ -108,49 +100,40 @@ function shouldFilter(options, name) {
 }
 
 function collectUsageData(ast, options) {
-  function walk(items, usageData) {
-    for (const item of items.children) {
-      // go deeper
-      if (item.type === 'root' || item.type === 'element') {
-        walk(item, usageData);
-      }
-
-      if (item.type === 'element') {
-        if (item.name === 'script') {
-          safe = false;
-        }
-
-        usageData.tags[item.name] = true;
-
-        if (item.attributes.id != null) {
-          usageData.ids[item.attributes.id] = true;
-        }
-
-        if (item.attributes.class != null) {
-          item.attributes.class
-            .replace(/^\s+|\s+$/g, '')
-            .split(/\s+/)
-            .forEach(function (className) {
-              usageData.classes[className] = true;
-            });
-        }
-
-        if (Object.keys(item.attributes).some((name) => /^on/i.test(name))) {
-          safe = false;
-        }
-      }
-    }
-
-    return usageData;
-  }
-
-  var safe = true;
-  var usageData = {};
-  var hasData = false;
-  var rawData = walk(ast, {
+  let safe = true;
+  const usageData = {};
+  let hasData = false;
+  const rawData = {
     ids: Object.create(null),
     classes: Object.create(null),
     tags: Object.create(null),
+  };
+
+  traverse(ast, (node) => {
+    if (node.type === 'element') {
+      if (node.name === 'script') {
+        safe = false;
+      }
+
+      rawData.tags[node.name] = true;
+
+      if (node.attributes.id != null) {
+        rawData.ids[node.attributes.id] = true;
+      }
+
+      if (node.attributes.class != null) {
+        node.attributes.class
+          .replace(/^\s+|\s+$/g, '')
+          .split(/\s+/)
+          .forEach((className) => {
+            rawData.classes[className] = true;
+          });
+      }
+
+      if (Object.keys(node.attributes).some((name) => /^on/i.test(name))) {
+        safe = false;
+      }
+    }
   });
 
   if (!safe && options.usage && options.usage.force) {
diff --git a/plugins/removeHiddenElems.js b/plugins/removeHiddenElems.js
index 7e531496..3277e040 100644
--- a/plugins/removeHiddenElems.js
+++ b/plugins/removeHiddenElems.js
@@ -1,5 +1,6 @@
 'use strict';
 
+const { querySelector, closestByName } = require('../lib/xast.js');
 const { computeStyle } = require('../lib/style.js');
 const { parsePathData } = require('../lib/path.js');
 
@@ -58,7 +59,7 @@ exports.fn = function (item, params) {
       computedStyle.visibility.type === 'static' &&
       computedStyle.visibility.value === 'hidden' &&
       // keep if any descendant enables visibility
-      item.querySelector('[visibility=visible]') == null
+      querySelector(item, '[visibility=visible]') == null
     ) {
       return false;
     }
@@ -88,7 +89,7 @@ exports.fn = function (item, params) {
       computedStyle.opacity.type === 'static' &&
       computedStyle.opacity.value === '0' &&
       // transparent element inside clipPath still affect clipped elements
-      item.closestElem('clipPath') == null
+      closestByName(item, 'clipPath') == null
     ) {
       return false;
     }
diff --git a/plugins/removeUnusedNS.js b/plugins/removeUnusedNS.js
index cbe598b2..80c0c27a 100644
--- a/plugins/removeUnusedNS.js
+++ b/plugins/removeUnusedNS.js
@@ -1,5 +1,6 @@
 'use strict';
 
+const { traverse } = require('../lib/xast.js');
 const { parseName } = require('../lib/svgo/tools.js');
 
 exports.type = 'full';
@@ -16,7 +17,7 @@ exports.description = 'removes unused namespaces declaration';
  *
  * @author Kir Belevich
  */
-exports.fn = function (data) {
+exports.fn = function (root) {
   let svgElem;
   const xmlnsCollection = [];
 
@@ -34,64 +35,46 @@ exports.fn = function (data) {
     }
   }
 
-  /**
-   * Bananas!
-   *
-   * @param {Array} items input items
-   *
-   * @return {Array} output items
-   */
-  function monkeys(items) {
-    for (const item of items.children) {
-      if (item.type === 'element') {
-        if (item.name === 'svg') {
-          for (const name of Object.keys(item.attributes)) {
-            const { prefix, local } = parseName(name);
-            // collect namespaces
-            if (prefix === 'xmlns' && local) {
-              xmlnsCollection.push(local);
-            }
-          }
-
-          // if svg element has ns-attr
-          if (xmlnsCollection.length) {
-            // save svg element
-            svgElem = item;
+  traverse(root, (node) => {
+    if (node.type === 'element') {
+      if (node.name === 'svg') {
+        for (const name of Object.keys(node.attributes)) {
+          const { prefix, local } = parseName(name);
+          // collect namespaces
+          if (prefix === 'xmlns' && local) {
+            xmlnsCollection.push(local);
           }
         }
 
+        // if svg element has ns-attr
         if (xmlnsCollection.length) {
-          const { prefix } = parseName(item.name);
-          // check item for the ns-attrs
-          if (prefix) {
-            removeNSfromCollection(prefix);
-          }
+          // save svg element
+          svgElem = node;
+        }
+      }
 
-          // check each attr for the ns-attrs
-          for (const name of Object.keys(item.attributes)) {
-            const { prefix } = parseName(name);
-            removeNSfromCollection(prefix);
-          }
+      if (xmlnsCollection.length) {
+        const { prefix } = parseName(node.name);
+        // check node for the ns-attrs
+        if (prefix) {
+          removeNSfromCollection(prefix);
         }
 
-        // if nothing is found - go deeper
-        if (xmlnsCollection.length && item.children) {
-          monkeys(item);
+        // check each attr for the ns-attrs
+        for (const name of Object.keys(node.attributes)) {
+          const { prefix } = parseName(name);
+          removeNSfromCollection(prefix);
         }
       }
     }
-
-    return items;
-  }
-
-  data = monkeys(data);
+  });
 
   // remove svg element ns-attributes if they are not used even once
   if (xmlnsCollection.length) {
-    xmlnsCollection.forEach(function (name) {
+    for (const name of xmlnsCollection) {
       delete svgElem.attributes['xmlns:' + name];
-    });
+    }
   }
 
-  return data;
+  return root;
 };
diff --git a/plugins/removeViewBox.js b/plugins/removeViewBox.js
index 2b9bf74e..ffcfb5c5 100644
--- a/plugins/removeViewBox.js
+++ b/plugins/removeViewBox.js
@@ -1,5 +1,7 @@
 'use strict';
 
+const { closestByName } = require('../lib/xast.js');
+
 exports.type = 'perItem';
 
 exports.active = true;
@@ -32,7 +34,7 @@ exports.fn = function (item) {
     item.attributes.height != null
   ) {
     // TODO remove width/height for such case instead
-    if (item.name === 'svg' && item.closestElem('svg')) {
+    if (item.name === 'svg' && closestByName(item.parentNode, 'svg')) {
       return;
     }
 
diff --git a/plugins/reusePaths.js b/plugins/reusePaths.js
index 3748cd03..f3eb6b6b 100644
--- a/plugins/reusePaths.js
+++ b/plugins/reusePaths.js
@@ -1,6 +1,7 @@
 'use strict';
 
-var JSAPI = require('../lib/svgo/jsAPI');
+const { traverse } = require('../lib/xast.js');
+const JSAPI = require('../lib/svgo/jsAPI');
 
 exports.type = 'full';
 
@@ -17,25 +18,25 @@ exports.description =
  *
  * @author Jacob Howcroft
  */
-exports.fn = function (data) {
+exports.fn = function (root) {
   const seen = new Map();
   let count = 0;
   const defs = [];
-  traverse(data, (item) => {
+  traverse(root, (node) => {
     if (
-      item.type !== 'element' ||
-      item.name !== 'path' ||
-      item.attributes.d == null
+      node.type !== 'element' ||
+      node.name !== 'path' ||
+      node.attributes.d == null
     ) {
       return;
     }
-    const d = item.attributes.d;
-    const fill = item.attributes.fill || '';
-    const stroke = item.attributes.stroke || '';
+    const d = node.attributes.d;
+    const fill = node.attributes.fill || '';
+    const stroke = node.attributes.stroke || '';
     const key = d + ';s:' + stroke + ';f:' + fill;
     const hasSeen = seen.get(key);
     if (!hasSeen) {
-      seen.set(key, { elem: item, reused: false });
+      seen.set(key, { elem: node, reused: false });
       return;
     }
     if (!hasSeen.reused) {
@@ -45,7 +46,7 @@ exports.fn = function (data) {
       }
       defs.push(hasSeen.elem);
     }
-    convertToUse(item, hasSeen.elem.attributes.id);
+    convertToUse(node, hasSeen.elem.attributes.id);
   });
   if (defs.length > 0) {
     const defsTag = new JSAPI(
@@ -55,9 +56,9 @@ exports.fn = function (data) {
         attributes: {},
         children: [],
       },
-      data
+      root
     );
-    data.children[0].spliceContent(0, 0, defsTag);
+    root.children[0].spliceContent(0, 0, defsTag);
     for (let def of defs) {
       // Remove class and style before copying to avoid circular refs in
       // JSON.stringify. This is fine because we don't actually want class or
@@ -76,7 +77,7 @@ exports.fn = function (data) {
       delete def.attributes.id;
     }
   }
-  return data;
+  return root;
 };
 
 /** */
@@ -89,13 +90,3 @@ function convertToUse(item, href) {
   delete item.pathJS;
   return item;
 }
-
-/** */
-function traverse(parent, callback) {
-  if (parent.type === 'root' || parent.type === 'element') {
-    for (let child of parent.children) {
-      callback(child);
-      traverse(child, callback);
-    }
-  }
-}