diff --git a/lib/css-tools.js b/lib/css-tools.js
index a6a343c7..101c093f 100644
--- a/lib/css-tools.js
+++ b/lib/css-tools.js
@@ -189,8 +189,8 @@ function csstreeToStyleDeclaration(declaration) {
  * @return {string} CSS string or empty array if no styles are set
  */
 function getCssStr(elem) {
-  if (elem.content[0].type === 'text' || elem.content[0].type === 'cdata') {
-    return elem.content[0].value;
+  if (elem.children[0].type === 'text' || elem.children[0].type === 'cdata') {
+    return elem.children[0].value;
   }
   return '';
 }
@@ -203,9 +203,9 @@ function getCssStr(elem) {
  * @return {string} reference to field with CSS
  */
 function setCssStr(elem, css) {
-  if (elem.content[0].type === 'text' || elem.content[0].type === 'cdata') {
-    elem.content[0].value = css;
-    return elem.content[0].value;
+  if (elem.children[0].type === 'text' || elem.children[0].type === 'cdata') {
+    elem.children[0].value = css;
+    return elem.children[0].value;
   }
   return css;
 }
diff --git a/lib/style.js b/lib/style.js
index c737cf6a..ef4dad0c 100644
--- a/lib/style.js
+++ b/lib/style.js
@@ -151,7 +151,7 @@ const computeStyle = (node) => {
       styleNode.attributes.type === '' ||
       styleNode.attributes.type === 'text/css'
     ) {
-      const children = styleNode.content || [];
+      const children = styleNode.children;
       for (const child of children) {
         if (child.type === 'text' || child.type === 'cdata') {
           stylesheet.push(...parseStylesheet(child.value, dynamic));
diff --git a/lib/svgo/css-select-adapter.js b/lib/svgo/css-select-adapter.js
index e7e5c394..0d01f06f 100644
--- a/lib/svgo/css-select-adapter.js
+++ b/lib/svgo/css-select-adapter.js
@@ -23,7 +23,7 @@ const getAttributeValue = (elem, name) => {
 };
 
 const getChildren = (node) => {
-  return node.content || [];
+  return node.children || [];
 };
 
 const getName = (elemAst) => {
@@ -40,8 +40,8 @@ const getSiblings = (elem) => {
 };
 
 const getText = (node) => {
-  if (node.content[0].type === 'text' && node.content[0].type === 'cdata') {
-    return node.content[0].value;
+  if (node.children[0].type === 'text' && node.children[0].type === 'cdata') {
+    return node.children[0].value;
   }
   return '';
 };
diff --git a/lib/svgo/js2svg.js b/lib/svgo/js2svg.js
index c1a4997d..1c9cf5c6 100644
--- a/lib/svgo/js2svg.js
+++ b/lib/svgo/js2svg.js
@@ -93,29 +93,27 @@ function encodeEntity(char) {
 JS2SVG.prototype.convert = function (data) {
   var svg = '';
 
-  if (data.content) {
-    this.indentLevel++;
+  this.indentLevel++;
 
-    data.content.forEach(function (item) {
-      if (item.type === 'element') {
-        svg += this.createElem(item);
-      }
-      if (item.type === 'text') {
-        svg += this.createText(item);
-      }
-      if (item.type === 'doctype') {
-        svg += this.createDoctype(item);
-      }
-      if (item.type === 'instruction') {
-        svg += this.createProcInst(item);
-      }
-      if (item.type === 'comment') {
-        svg += this.createComment(item);
-      }
-      if (item.type === 'cdata') {
-        svg += this.createCDATA(item);
-      }
-    }, this);
+  for (const item of data.children) {
+    if (item.type === 'element') {
+      svg += this.createElem(item);
+    }
+    if (item.type === 'text') {
+      svg += this.createText(item);
+    }
+    if (item.type === 'doctype') {
+      svg += this.createDoctype(item);
+    }
+    if (item.type === 'instruction') {
+      svg += this.createProcInst(item);
+    }
+    if (item.type === 'comment') {
+      svg += this.createComment(item);
+    }
+    if (item.type === 'cdata') {
+      svg += this.createCDATA(item);
+    }
   }
 
   this.indentLevel--;
@@ -211,7 +209,7 @@ JS2SVG.prototype.createElem = function (data) {
   }
 
   // empty element and short tag
-  if (data.isEmpty()) {
+  if (data.children.length === 0) {
     if (this.config.useShortTags) {
       return (
         this.createIndent() +
diff --git a/lib/svgo/jsAPI.js b/lib/svgo/jsAPI.js
index b3cf989b..165e0dfe 100644
--- a/lib/svgo/jsAPI.js
+++ b/lib/svgo/jsAPI.js
@@ -30,7 +30,7 @@ JSAPI.prototype.clone = function () {
   var nodeData = {};
 
   Object.keys(node).forEach(function (key) {
-    if (key !== 'class' && key !== 'style' && key !== 'content') {
+    if (key !== 'class' && key !== 'style' && key !== 'children') {
       nodeData[key] = node[key];
     }
   });
@@ -49,8 +49,8 @@ JSAPI.prototype.clone = function () {
   if (node.style) {
     clonedNode.style = node.style.clone(clonedNode);
   }
-  if (node.content) {
-    clonedNode.content = node.content.map(function (childNode) {
+  if (node.children) {
+    clonedNode.children = node.children.map(function (childNode) {
       var clonedChild = childNode.clone();
       clonedChild.parentNode = clonedNode;
       return clonedChild;
@@ -98,7 +98,7 @@ JSAPI.prototype.renameElem = function (name) {
  * @return {Boolean}
  */
 JSAPI.prototype.isEmpty = function () {
-  return !this.content || !this.content.length;
+  return !this.children || !this.children.length;
 };
 
 /**
@@ -116,11 +116,11 @@ JSAPI.prototype.closestElem = function (elemName) {
 };
 
 /**
- * Changes content by removing elements and/or adding new elements.
+ * Changes children by removing elements and/or adding new elements.
  *
- * @param {Number} start Index at which to start changing the content.
+ * @param {Number} start Index at which to start changing the children.
  * @param {Number} n Number of elements to remove.
- * @param {Array|Object} [insertion] Elements to add to the content.
+ * @param {Array|Object} [insertion] Elements to add to the children.
  * @return {Array} Removed elements.
  */
 JSAPI.prototype.spliceContent = function (start, n, insertion) {
@@ -133,7 +133,10 @@ JSAPI.prototype.spliceContent = function (start, n, insertion) {
     inner.parentNode = this;
   }, this);
 
-  return this.content.splice.apply(this.content, [start, n].concat(insertion));
+  return this.children.splice.apply(
+    this.children,
+    [start, n].concat(insertion)
+  );
 };
 
 /**
diff --git a/lib/svgo/plugins.js b/lib/svgo/plugins.js
index f99e7fe9..4e1926cd 100644
--- a/lib/svgo/plugins.js
+++ b/lib/svgo/plugins.js
@@ -50,9 +50,9 @@ module.exports = function (data, info, plugins) {
  */
 function perItem(data, info, plugins, reverse) {
   function monkeys(items) {
-    items.content = items.content.filter(function (item) {
+    items.children = items.children.filter(function (item) {
       // reverse pass
-      if (reverse && item.content) {
+      if (reverse && item.children) {
         monkeys(item);
       }
 
@@ -68,7 +68,7 @@ function perItem(data, info, plugins, reverse) {
       }
 
       // direct pass
-      if (!reverse && item.content) {
+      if (!reverse && item.children) {
         monkeys(item);
       }
 
diff --git a/lib/svgo/svg2js.js b/lib/svgo/svg2js.js
index 5a747290..3005711f 100644
--- a/lib/svgo/svg2js.js
+++ b/lib/svgo/svg2js.js
@@ -23,13 +23,13 @@ var config = {
  */
 module.exports = function (data) {
   var sax = SAX.parser(config.strict, config),
-    root = new JSAPI({ type: 'root', content: [] }),
+    root = new JSAPI({ type: 'root', children: [] }),
     current = root,
     stack = [root];
 
-  function pushToContent(content) {
-    const wrapped = new JSAPI(content, current);
-    current.content.push(wrapped);
+  function pushToContent(node) {
+    const wrapped = new JSAPI(node, current);
+    current.children.push(wrapped);
     return wrapped;
   }
 
@@ -128,7 +128,7 @@ module.exports = function (data) {
         }
         element.attributes = newAttributes;
       },
-      content: [],
+      children: [],
     };
 
     element.class = new CSSClassList(element);
diff --git a/plugins/addAttributesToSVGElement.js b/plugins/addAttributesToSVGElement.js
index 2a3ab0a8..dfe6ce50 100644
--- a/plugins/addAttributesToSVGElement.js
+++ b/plugins/addAttributesToSVGElement.js
@@ -57,7 +57,7 @@ exports.fn = function (data, params) {
   }
 
   var attributes = params.attributes || [params.attribute],
-    svg = data.content[0];
+    svg = data.children[0];
 
   if (svg.isElem('svg')) {
     attributes.forEach(function (attribute) {
diff --git a/plugins/addClassesToSVGElement.js b/plugins/addClassesToSVGElement.js
index c8d195a9..dcecadbe 100644
--- a/plugins/addClassesToSVGElement.js
+++ b/plugins/addClassesToSVGElement.js
@@ -45,7 +45,7 @@ exports.fn = function (data, params) {
   }
 
   var classNames = params.classNames || [params.className],
-    svg = data.content[0];
+    svg = data.children[0];
 
   if (svg.isElem('svg')) {
     svg.class.add.apply(svg.class, classNames);
diff --git a/plugins/cleanupEnableBackground.js b/plugins/cleanupEnableBackground.js
index 399c153d..2369d6c0 100644
--- a/plugins/cleanupEnableBackground.js
+++ b/plugins/cleanupEnableBackground.js
@@ -60,10 +60,10 @@ exports.fn = function (data) {
   }
 
   function monkeys(items, fn) {
-    items.content.forEach(function (item) {
+    items.children.forEach(function (item) {
       fn(item);
 
-      if (item.content) {
+      if (item.children) {
         monkeys(item, fn);
       }
     });
diff --git a/plugins/cleanupIDs.js b/plugins/cleanupIDs.js
index 83aedf4f..1a7e5558 100644
--- a/plugins/cleanupIDs.js
+++ b/plugins/cleanupIDs.js
@@ -117,13 +117,12 @@ exports.fn = function (data, params) {
    * @return {Array} output items
    */
   function monkeys(items) {
-    for (var i = 0; i < items.content.length && !hasStyleOrScript; i++) {
-      var item = items.content[i];
+    for (var i = 0; i < items.children.length && !hasStyleOrScript; i++) {
+      var item = items.children[i];
 
       // quit if <style> or <script> present ('force' param prevents quitting)
       if (!params.force) {
-        var isNotEmpty = item.isEmpty() === false;
-        if (item.isElem(styleOrScript) && isNotEmpty) {
+        if (item.isElem(styleOrScript) && item.children.length !== 0) {
           hasStyleOrScript = true;
           continue;
         }
@@ -132,8 +131,8 @@ exports.fn = function (data, params) {
         if (item.isElem('svg')) {
           var hasDefsOnly = true;
 
-          for (var j = 0; j < item.content.length; j++) {
-            if (!item.content[j].isElem('defs')) {
+          for (var j = 0; j < item.children.length; j++) {
+            if (!item.children[j].isElem('defs')) {
               hasDefsOnly = false;
               break;
             }
@@ -181,7 +180,7 @@ exports.fn = function (data, params) {
         });
       }
       // go deeper
-      if (item.content) {
+      if (item.children) {
         monkeys(item);
       }
     }
diff --git a/plugins/collapseGroups.js b/plugins/collapseGroups.js
index 83f9f175..9d69b003 100644
--- a/plugins/collapseGroups.js
+++ b/plugins/collapseGroups.js
@@ -13,7 +13,9 @@ var collections = require('./_collections'),
 function hasAnimatedAttr(item) {
   return (
     (item.isElem(animationElems) && item.hasAttr('attributeName', this)) ||
-    (!item.isEmpty() && item.content.some(hasAnimatedAttr, this))
+    (item.type === 'element' &&
+      item.children.length !== 0 &&
+      item.children.some(hasAnimatedAttr, this))
   );
 }
 
@@ -42,13 +44,17 @@ function hasAnimatedAttr(item) {
  */
 exports.fn = function (item) {
   // non-empty elements
-  if (item.type === 'element' && !item.isElem('switch') && !item.isEmpty()) {
-    item.content.forEach(function (g, i) {
+  if (
+    item.type === 'element' &&
+    !item.isElem('switch') &&
+    item.children.length !== 0
+  ) {
+    item.children.forEach(function (g, i) {
       // non-empty groups
-      if (g.isElem('g') && !g.isEmpty()) {
-        // move group attibutes to the single content element
-        if (g.hasAttr() && g.content.length === 1) {
-          var inner = g.content[0];
+      if (g.isElem('g') && g.children.length !== 0) {
+        // move group attibutes to the single child element
+        if (g.hasAttr() && g.children.length === 1) {
+          var inner = g.children[0];
 
           if (
             inner.type === 'element' &&
@@ -61,7 +67,7 @@ exports.fn = function (item) {
                 !inner.hasAttr('transform')))
           ) {
             g.eachAttr(function (attr) {
-              if (g.content.some(hasAnimatedAttr, attr.name)) return;
+              if (g.children.some(hasAnimatedAttr, attr.name)) return;
 
               if (!inner.hasAttr(attr.name)) {
                 inner.addAttr(attr);
@@ -85,11 +91,11 @@ exports.fn = function (item) {
         // collapse groups without attributes
         if (
           !g.hasAttr() &&
-          !g.content.some(function (item) {
+          !g.children.some(function (item) {
             return item.isElem(animationElems);
           })
         ) {
-          item.spliceContent(i, 1, g.content);
+          item.spliceContent(i, 1, g.children);
         }
       }
     });
diff --git a/plugins/inlineStyles.js b/plugins/inlineStyles.js
index 5c5fca6a..67e1bdc7 100644
--- a/plugins/inlineStyles.js
+++ b/plugins/inlineStyles.js
@@ -62,7 +62,7 @@ exports.fn = function (document, opts) {
       continue;
     }
     // skip empty <style/>s or <foreignObject> content.
-    if (styleEl.isEmpty() || styleEl.closestElem('foreignObject')) {
+    if (styleEl.children.length === 0 || styleEl.closestElem('foreignObject')) {
       continue;
     }
 
@@ -244,15 +244,18 @@ exports.fn = function (document, opts) {
       // clean up now emtpy <style/>s
       var styleParentEl = style.styleEl.parentNode;
       styleParentEl.spliceContent(
-        styleParentEl.content.indexOf(style.styleEl),
+        styleParentEl.children.indexOf(style.styleEl),
         1
       );
 
-      if (styleParentEl.name === 'defs' && styleParentEl.content.length === 0) {
+      if (
+        styleParentEl.name === 'defs' &&
+        styleParentEl.children.length === 0
+      ) {
         // also clean up now empty <def/>s
         var defsParentEl = styleParentEl.parentNode;
         defsParentEl.spliceContent(
-          defsParentEl.content.indexOf(styleParentEl),
+          defsParentEl.children.indexOf(styleParentEl),
           1
         );
       }
diff --git a/plugins/mergePaths.js b/plugins/mergePaths.js
index 9f0331ae..3e88ad0f 100644
--- a/plugins/mergePaths.js
+++ b/plugins/mergePaths.js
@@ -26,19 +26,19 @@ exports.params = {
  * @author Kir Belevich, Lev Solntsev
  */
 exports.fn = function (item, params) {
-  if (item.type !== 'element' || item.isEmpty()) return;
+  if (item.type !== 'element' || item.children.length === 0) return;
 
   var prevContentItem = null,
     prevContentItemKeys = null;
 
-  item.content = item.content.filter(function (contentItem) {
+  item.children = item.children.filter(function (contentItem) {
     if (
       prevContentItem &&
       prevContentItem.isElem('path') &&
-      prevContentItem.isEmpty() &&
+      prevContentItem.children.length === 0 &&
       prevContentItem.hasAttr('d') &&
       contentItem.isElem('path') &&
-      contentItem.isEmpty() &&
+      contentItem.children.length === 0 &&
       contentItem.hasAttr('d')
     ) {
       const computedStyle = computeStyle(contentItem);
diff --git a/plugins/minifyStyles.js b/plugins/minifyStyles.js
index ff9bf131..f586e27d 100755
--- a/plugins/minifyStyles.js
+++ b/plugins/minifyStyles.js
@@ -38,17 +38,20 @@ exports.fn = function (ast, options) {
 
   elems.forEach(function (elem) {
     if (elem.isElem('style')) {
-      if (elem.content[0].type === 'text' || elem.content[0].type === 'cdata') {
-        const styleCss = elem.content[0].value;
+      if (
+        elem.children[0].type === 'text' ||
+        elem.children[0].type === 'cdata'
+      ) {
+        const styleCss = elem.children[0].value;
         const minified = csso.minify(styleCss, minifyOptionsForStylesheet).css;
         // preserve cdata if necessary
         // TODO split cdata -> text optimisation into separate plugin
         if (styleCss.indexOf('>') >= 0 || styleCss.indexOf('<') >= 0) {
-          elem.content[0].type = 'cdata';
-          elem.content[0].value = minified;
+          elem.children[0].type = 'cdata';
+          elem.children[0].value = minified;
         } else {
-          elem.content[0].type = 'text';
-          elem.content[0].value = minified;
+          elem.children[0].type = 'text';
+          elem.children[0].value = minified;
         }
       }
     } else {
@@ -71,15 +74,15 @@ function cloneObject(obj) {
 
 function findStyleElems(ast) {
   function walk(items, styles) {
-    for (var i = 0; i < items.content.length; i++) {
-      var item = items.content[i];
+    for (var i = 0; i < items.children.length; i++) {
+      var item = items.children[i];
 
       // go deeper
-      if (item.content) {
+      if (item.children) {
         walk(item, styles);
       }
 
-      if (item.isElem('style') && !item.isEmpty()) {
+      if (item.isElem('style') && item.children.length !== 0) {
         styles.push(item);
       } else if (item.type === 'element' && item.hasAttr('style')) {
         styles.push(item);
@@ -106,11 +109,11 @@ function shouldFilter(options, name) {
 
 function collectUsageData(ast, options) {
   function walk(items, usageData) {
-    for (var i = 0; i < items.content.length; i++) {
-      var item = items.content[i];
+    for (var i = 0; i < items.children.length; i++) {
+      var item = items.children[i];
 
       // go deeper
-      if (item.content) {
+      if (item.children) {
         walk(item, usageData);
       }
 
diff --git a/plugins/moveElemsAttrsToGroup.js b/plugins/moveElemsAttrsToGroup.js
index 4a6c799d..66eb741f 100644
--- a/plugins/moveElemsAttrsToGroup.js
+++ b/plugins/moveElemsAttrsToGroup.js
@@ -34,11 +34,11 @@ var inheritableAttrs = require('./_collections').inheritableAttrs,
  * @author Kir Belevich
  */
 exports.fn = function (item) {
-  if (item.isElem('g') && !item.isEmpty() && item.content.length > 1) {
+  if (item.isElem('g') && item.children.length > 1) {
     var intersection = {},
       hasTransform = false,
       hasClip = item.hasAttr('clip-path') || item.hasAttr('mask'),
-      intersected = item.content.every(function (inner) {
+      intersected = item.children.every(function (inner) {
         if (inner.type === 'element' && inner.hasAttr()) {
           // don't mess with possible styles (hack until CSS parsing is implemented)
           if (inner.hasAttr('class')) return false;
@@ -56,12 +56,12 @@ exports.fn = function (item) {
           return true;
         }
       }),
-      allPath = item.content.every(function (inner) {
+      allPath = item.children.every(function (inner) {
         return inner.isElem(pathElems);
       });
 
     if (intersected) {
-      item.content.forEach(function (g) {
+      item.children.forEach(function (g) {
         for (const [name, value] of Object.entries(intersection)) {
           if ((!allPath && !hasClip) || name !== 'transform') {
             g.removeAttr(name);
diff --git a/plugins/moveGroupAttrsToElems.js b/plugins/moveGroupAttrsToElems.js
index 63e9dc1b..bb7b9ac0 100644
--- a/plugins/moveGroupAttrsToElems.js
+++ b/plugins/moveGroupAttrsToElems.js
@@ -33,16 +33,16 @@ exports.fn = function (item) {
   // move group transform attr to content's pathElems
   if (
     item.isElem('g') &&
+    item.children.length !== 0 &&
     item.hasAttr('transform') &&
-    !item.isEmpty() &&
     !item.someAttr(function (attr) {
       return ~referencesProps.indexOf(attr.name) && ~attr.value.indexOf('url(');
     }) &&
-    item.content.every(function (inner) {
+    item.children.every(function (inner) {
       return inner.isElem(pathElems) && !inner.hasAttr('id');
     })
   ) {
-    item.content.forEach(function (inner) {
+    item.children.forEach(function (inner) {
       var attr = item.attr('transform');
       if (inner.hasAttr('transform')) {
         inner.attr('transform').value =
diff --git a/plugins/prefixIds.js b/plugins/prefixIds.js
index 2fd11517..22b78841 100755
--- a/plugins/prefixIds.js
+++ b/plugins/prefixIds.js
@@ -197,15 +197,15 @@ exports.fn = function (node, opts, extra) {
 
   // <style/> property values
 
-  if (node.name === 'style') {
-    if (node.isEmpty()) {
+  if (node.type === 'element' && node.name === 'style') {
+    if (node.children.length === 0) {
       // skip empty <style/>s
       return node;
     }
 
     var cssStr = '';
-    if (node.content[0].type === 'text' || node.content[0].type === 'cdata') {
-      cssStr = node.content[0].value;
+    if (node.children[0].type === 'text' || node.children[0].type === 'cdata') {
+      cssStr = node.children[0].value;
     }
 
     var cssAst = {};
@@ -249,7 +249,7 @@ exports.fn = function (node, opts, extra) {
     });
 
     // update <style>s
-    node.content[0].value = csstree.generate(cssAst);
+    node.children[0].value = csstree.generate(cssAst);
     return node;
   }
 
diff --git a/plugins/removeDesc.js b/plugins/removeDesc.js
index d4a3d17e..4616109c 100644
--- a/plugins/removeDesc.js
+++ b/plugins/removeDesc.js
@@ -29,9 +29,9 @@ exports.fn = function (item, params) {
     !item.isElem('desc') ||
     !(
       params.removeAny ||
-      item.isEmpty() ||
-      (item.content[0].type === 'text' &&
-        standardDescs.test(item.content[0].value))
+      item.children.length === 0 ||
+      (item.children[0].type === 'text' &&
+        standardDescs.test(item.children[0].value))
     )
   );
 };
diff --git a/plugins/removeEmptyContainers.js b/plugins/removeEmptyContainers.js
index f34e5108..c8d6492b 100644
--- a/plugins/removeEmptyContainers.js
+++ b/plugins/removeEmptyContainers.js
@@ -27,7 +27,7 @@ var container = require('./_collections').elemsGroups.container;
 exports.fn = function (item) {
   return (
     item.isElem(container) === false ||
-    item.isEmpty() === false ||
+    (item.type === 'element' && item.children.length !== 0) ||
     item.isElem('svg') ||
     // empty patterns may contain reusable configuration
     (item.isElem('pattern') && Object.keys(item.attrs).length !== 0) ||
diff --git a/plugins/removeEmptyText.js b/plugins/removeEmptyText.js
index d7eef1d8..89b4644c 100644
--- a/plugins/removeEmptyText.js
+++ b/plugins/removeEmptyText.js
@@ -35,12 +35,17 @@ exports.params = {
  */
 exports.fn = function (item, params) {
   // Remove empty text element
-  if (params.text && item.isElem('text') && item.isEmpty()) return false;
+  if (params.text && item.isElem('text') && item.children.length === 0) {
+    return false;
+  }
 
   // Remove empty tspan element
-  if (params.tspan && item.isElem('tspan') && item.isEmpty()) return false;
+  if (params.tspan && item.isElem('tspan') && item.children.length === 0) {
+    return false;
+  }
 
   // Remove tref with empty xlink:href attribute
-  if (params.tref && item.isElem('tref') && !item.hasAttrLocal('href'))
+  if (params.tref && item.isElem('tref') && !item.hasAttrLocal('href')) {
     return false;
+  }
 };
diff --git a/plugins/removeHiddenElems.js b/plugins/removeHiddenElems.js
index 05b59986..c69f8b90 100644
--- a/plugins/removeHiddenElems.js
+++ b/plugins/removeHiddenElems.js
@@ -102,7 +102,7 @@ exports.fn = function (item, params) {
     if (
       params.circleR0 &&
       item.isElem('circle') &&
-      item.isEmpty() &&
+      item.children.length === 0 &&
       item.hasAttr('r', '0')
     ) {
       return false;
@@ -117,7 +117,7 @@ exports.fn = function (item, params) {
     if (
       params.ellipseRX0 &&
       item.isElem('ellipse') &&
-      item.isEmpty() &&
+      item.children.length === 0 &&
       item.hasAttr('rx', '0')
     ) {
       return false;
@@ -132,7 +132,7 @@ exports.fn = function (item, params) {
     if (
       params.ellipseRY0 &&
       item.isElem('ellipse') &&
-      item.isEmpty() &&
+      item.children.length === 0 &&
       item.hasAttr('ry', '0')
     ) {
       return false;
@@ -147,7 +147,7 @@ exports.fn = function (item, params) {
     if (
       params.rectWidth0 &&
       item.isElem('rect') &&
-      item.isEmpty() &&
+      item.children.length === 0 &&
       item.hasAttr('width', '0')
     ) {
       return false;
@@ -163,7 +163,7 @@ exports.fn = function (item, params) {
       params.rectHeight0 &&
       params.rectWidth0 &&
       item.isElem('rect') &&
-      item.isEmpty() &&
+      item.children.length === 0 &&
       item.hasAttr('height', '0')
     ) {
       return false;
diff --git a/plugins/removeUnknownsAndDefaults.js b/plugins/removeUnknownsAndDefaults.js
index 619e86c4..e2d29bcd 100644
--- a/plugins/removeUnknownsAndDefaults.js
+++ b/plugins/removeUnknownsAndDefaults.js
@@ -74,11 +74,10 @@ exports.fn = function (item, params) {
     // remove unknown element's content
     if (
       params.unknownContent &&
-      !item.isEmpty() &&
       elems[elem] && // make sure we know of this element before checking its children
       elem !== 'foreignObject' // Don't check foreignObject
     ) {
-      item.content.forEach(function (content, i) {
+      item.children.forEach(function (content, i) {
         if (
           content.type === 'element' &&
           !parseName(content.name).prefix &&
@@ -87,7 +86,7 @@ exports.fn = function (item, params) {
             (!elems[elem].content && // we dont know about its permitted content
               !elems[content.name])) // check that we know about the element at all
         ) {
-          item.content.splice(i, 1);
+          item.children.splice(i, 1);
         }
       });
     }
diff --git a/plugins/removeUnusedNS.js b/plugins/removeUnusedNS.js
index 75e4421e..6426ac9a 100644
--- a/plugins/removeUnusedNS.js
+++ b/plugins/removeUnusedNS.js
@@ -43,10 +43,10 @@ exports.fn = function (data) {
    */
   function monkeys(items) {
     var i = 0,
-      length = items.content.length;
+      length = items.children.length;
 
     while (i < length) {
-      var item = items.content[i];
+      var item = items.children[i];
 
       if (item.isElem('svg')) {
         item.eachAttr(function (attr) {
@@ -79,7 +79,7 @@ exports.fn = function (data) {
       }
 
       // if nothing is found - go deeper
-      if (xmlnsCollection.length && item.content) {
+      if (xmlnsCollection.length && item.children) {
         monkeys(item);
       }
 
diff --git a/plugins/removeUselessDefs.js b/plugins/removeUselessDefs.js
index aa9fd441..70516364 100644
--- a/plugins/removeUselessDefs.js
+++ b/plugins/removeUselessDefs.js
@@ -18,25 +18,26 @@ var nonRendering = require('./_collections').elemsGroups.nonRendering;
  */
 exports.fn = function (item) {
   if (item.isElem('defs')) {
-    if (item.content) {
-      item.content = getUsefulItems(item, []);
+    item.children = getUsefulItems(item, []);
+    if (item.children.length === 0) {
+      return false;
     }
-
-    if (item.isEmpty()) return false;
   } else if (item.isElem(nonRendering) && !item.hasAttr('id')) {
     return false;
   }
 };
 
 function getUsefulItems(item, usefulItems) {
-  item.content.forEach(function (child) {
-    if (child.hasAttr('id') || child.isElem('style')) {
-      usefulItems.push(child);
-      child.parentNode = item;
-    } else if (!child.isEmpty()) {
-      child.content = getUsefulItems(child, usefulItems);
+  for (const child of item.children) {
+    if (child.type === 'element') {
+      if (child.hasAttr('id') || child.isElem('style')) {
+        usefulItems.push(child);
+        child.parentNode = item;
+      } else {
+        child.children = getUsefulItems(child, usefulItems);
+      }
     }
-  });
+  }
 
   return usefulItems;
 }
diff --git a/plugins/reusePaths.js b/plugins/reusePaths.js
index 3bc6071e..cc80c3ed 100644
--- a/plugins/reusePaths.js
+++ b/plugins/reusePaths.js
@@ -51,12 +51,12 @@ exports.fn = function (data) {
       {
         type: 'element',
         name: 'defs',
-        content: [],
-        attrs: [],
+        children: [],
+        attrs: {},
       },
       data
     );
-    data.content[0].spliceContent(0, 0, defsTag);
+    data.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
@@ -94,11 +94,10 @@ function convertToUse(item, href) {
 
 /** */
 function traverse(parent, callback) {
-  if (parent.isEmpty()) {
-    return;
-  }
-  for (let child of parent.content) {
-    callback(child);
-    traverse(child, callback);
+  if (parent.type === 'root' || parent.type === 'element') {
+    for (let child of parent.children) {
+      callback(child);
+      traverse(child, callback);
+    }
   }
 }
diff --git a/plugins/sortDefsChildren.js b/plugins/sortDefsChildren.js
index fea76a95..3306a9aa 100644
--- a/plugins/sortDefsChildren.js
+++ b/plugins/sortDefsChildren.js
@@ -17,28 +17,25 @@ exports.description = 'Sorts children of <defs> to improve compression';
  */
 exports.fn = function (item) {
   if (item.isElem('defs')) {
-    if (item.content) {
-      var frequency = item.content.reduce(function (frequency, child) {
-        if (child.name in frequency) {
-          frequency[child.name]++;
-        } else {
-          frequency[child.name] = 1;
-        }
-        return frequency;
-      }, {});
-      item.content.sort(function (a, b) {
-        var frequencyComparison = frequency[b.name] - frequency[a.name];
-        if (frequencyComparison !== 0) {
-          return frequencyComparison;
-        }
-        var lengthComparison = b.name.length - a.name.length;
-        if (lengthComparison !== 0) {
-          return lengthComparison;
-        }
-        return a.name != b.name ? (a.name > b.name ? -1 : 1) : 0;
-      });
-    }
-
+    var frequency = item.children.reduce(function (frequency, child) {
+      if (child.name in frequency) {
+        frequency[child.name]++;
+      } else {
+        frequency[child.name] = 1;
+      }
+      return frequency;
+    }, {});
+    item.children.sort(function (a, b) {
+      var frequencyComparison = frequency[b.name] - frequency[a.name];
+      if (frequencyComparison !== 0) {
+        return frequencyComparison;
+      }
+      var lengthComparison = b.name.length - a.name.length;
+      if (lengthComparison !== 0) {
+        return lengthComparison;
+      }
+      return a.name != b.name ? (a.name > b.name ? -1 : 1) : 0;
+    });
     return true;
   }
 };
diff --git a/test/svg2js/_index.js b/test/svg2js/_index.js
index 14563989..0ca3aac2 100644
--- a/test/svg2js/_index.js
+++ b/test/svg2js/_index.js
@@ -34,23 +34,23 @@ describe('svg2js', function () {
         expect(root).to.be.an.instanceOf(Object);
       });
 
-      it('should have property "content"', function () {
-        expect(root).to.have.property('content');
+      it('should have property "children"', function () {
+        expect(root).to.have.property('children');
       });
     });
 
-    describe('root.content', function () {
+    describe('root.children', function () {
       it('should be an instance of Array', function () {
-        expect(root.content).to.be.an.instanceOf(Array);
+        expect(root.children).to.be.an.instanceOf(Array);
       });
 
       it('should have length 4', function () {
-        expect(root.content).to.have.lengthOf(4);
+        expect(root.children).to.have.lengthOf(4);
       });
     });
 
     it('the first node should be instruction', () => {
-      expect(root.content[0]).to.include({
+      expect(root.children[0]).to.include({
         type: 'instruction',
         name: 'xml',
         value: 'version="1.0" encoding="utf-8"',
@@ -58,7 +58,7 @@ describe('svg2js', function () {
     });
 
     it('the second node should be comment', () => {
-      expect(root.content[1]).to.include({
+      expect(root.children[1]).to.include({
         type: 'comment',
         value:
           'Generator: Adobe Illustrator 15.0.0, SVG Export Plug-In . SVG Version: 6.00 Build 0)',
@@ -66,7 +66,7 @@ describe('svg2js', function () {
     });
 
     it('the third node should be doctype', () => {
-      expect(root.content[2]).to.deep.include({
+      expect(root.children[2]).to.deep.include({
         type: 'doctype',
         name: 'svg',
         data: {
@@ -78,41 +78,41 @@ describe('svg2js', function () {
 
     describe('name', function () {
       it('should have property name: "svg"', function () {
-        expect(root.content[3]).to.include({
+        expect(root.children[3]).to.include({
           name: 'svg',
         });
       });
     });
 
     describe('attributes', function () {
-      describe('root.content[3].attrs', function () {
+      describe('root.children[3].attrs', function () {
         it('should exist', function () {
-          expect(root.content[3].attrs).to.exist;
+          expect(root.children[3].attrs).to.exist;
         });
 
         it('should be an instance of Object', function () {
-          expect(root.content[3].attrs).to.be.an.instanceOf(Object);
+          expect(root.children[3].attrs).to.be.an.instanceOf(Object);
         });
       });
 
-      describe('root.content[3].attrs.version', function () {
+      describe('root.children[3].attrs.version', function () {
         it('should exist', function () {
-          expect(root.content[3].attrs.version).to.exist;
+          expect(root.children[3].attrs.version).to.exist;
         });
 
         it('should be an instance of Object', function () {
-          expect(root.content[3].attrs.version).to.be.an.instanceOf(Object);
+          expect(root.children[3].attrs.version).to.be.an.instanceOf(Object);
         });
 
         it('should have property name: "version"', function () {
-          expect(root.content[3].attrs.version).to.have.property(
+          expect(root.children[3].attrs.version).to.have.property(
             'name',
             'version'
           );
         });
 
         it('should have property value: "1.1"', function () {
-          expect(root.content[3].attrs.version).to.have.property(
+          expect(root.children[3].attrs.version).to.have.property(
             'value',
             '1.1'
           );
@@ -120,45 +120,45 @@ describe('svg2js', function () {
       });
     });
 
-    describe('content', function () {
+    describe('children', function () {
       it('should exist', function () {
-        expect(root.content[3].content).to.exist;
+        expect(root.children[3].children).to.exist;
       });
 
       it('should be an instance of Array', function () {
-        expect(root.content[3].content).to.be.an.instanceOf(Array);
+        expect(root.children[3].children).to.be.an.instanceOf(Array);
       });
 
       it('should eventually have length 3', function () {
-        expect(root.content[3].content).to.have.lengthOf(3);
+        expect(root.children[3].children).to.have.lengthOf(3);
       });
     });
 
     describe('text nodes', function () {
       it('should contain preserved whitespace', function () {
-        const textNode = root.content[3].content[1].content[0].content[1];
-        return expect(textNode.content[0].value).to.equal('  test  ');
+        const textNode = root.children[3].children[1].children[0].children[1];
+        return expect(textNode.children[0].value).to.equal('  test  ');
       });
     });
 
     describe('API', function () {
       describe('clone()', function () {
         it('svg should have property "clone"', function () {
-          expect(root.content[3]).to.have.property('clone');
+          expect(root.children[3]).to.have.property('clone');
         });
 
         it('svg.clone() should be an instance of JSAPI', function () {
-          expect(root.content[3].clone()).to.be.instanceOf(JSAPI);
+          expect(root.children[3].clone()).to.be.instanceOf(JSAPI);
         });
 
-        it('root.content[3].content[0].clone() has a valid style property', function () {
-          expect(root.content[3].content[0].clone().style).to.be.instanceof(
+        it('root.children[3].children[0].clone() has a valid style property', function () {
+          expect(root.children[3].children[0].clone().style).to.be.instanceof(
             CSSStyleDeclaration
           );
         });
 
-        it('root.content[3].content[2].clone() has a valid class property', function () {
-          expect(root.content[3].content[2].clone().class).to.be.instanceof(
+        it('root.children[3].children[2].clone() has a valid class property', function () {
+          expect(root.children[3].children[2].clone().class).to.be.instanceof(
             CSSClassList
           );
         });
@@ -166,128 +166,129 @@ describe('svg2js', function () {
 
       describe('isElem()', function () {
         it('svg should have property "isElem"', function () {
-          expect(root.content[3]).to.have.property('isElem');
+          expect(root.children[3]).to.have.property('isElem');
         });
 
         it('svg.isElem() should be true', function () {
-          expect(root.content[3].isElem()).to.be.true;
+          expect(root.children[3].isElem()).to.be.true;
         });
 
         it('svg.isElem("svg") should be true', function () {
-          expect(root.content[3].isElem('svg')).to.be.true;
+          expect(root.children[3].isElem('svg')).to.be.true;
         });
 
         it('svg.isElem("trololo") should be false', function () {
-          expect(root.content[3].isElem('trololo')).to.be.false;
+          expect(root.children[3].isElem('trololo')).to.be.false;
         });
 
         it('svg.isElem(["svg", "trololo"]) should be true', function () {
-          expect(root.content[3].isElem(['svg', 'trololo'])).to.be.true;
+          expect(root.children[3].isElem(['svg', 'trololo'])).to.be.true;
         });
       });
 
       describe('isEmpty()', function () {
         it('svg should have property "isEmpty"', function () {
-          expect(root.content[3]).to.have.property('isEmpty');
+          expect(root.children[3]).to.have.property('isEmpty');
         });
 
         it('svg.isEmpty() should be false', function () {
-          expect(root.content[3].isEmpty()).to.be.false;
+          expect(root.children[3].isEmpty()).to.be.false;
         });
 
-        it('svg.content[0].content[0].isEmpty() should be true', function () {
-          expect(root.content[3].content[0].content[0].isEmpty()).to.be.true;
+        it('svg.children[0].children[0].isEmpty() should be true', function () {
+          expect(root.children[3].children[0].children[0].isEmpty()).to.be.true;
         });
       });
 
       describe('hasAttr()', function () {
         it('svg should have property "hasAttr"', function () {
-          expect(root.content[3]).to.have.property('hasAttr');
+          expect(root.children[3]).to.have.property('hasAttr');
         });
 
         it('svg.hasAttr() should be true', function () {
-          expect(root.content[3].hasAttr()).to.be.true;
+          expect(root.children[3].hasAttr()).to.be.true;
         });
 
         it('svg.hasAttr("xmlns") should be true', function () {
-          expect(root.content[3].hasAttr('xmlns')).to.be.true;
+          expect(root.children[3].hasAttr('xmlns')).to.be.true;
         });
 
         it('svg.hasAttr("xmlns", "http://www.w3.org/2000/svg") should be true', function () {
-          expect(root.content[3].hasAttr('xmlns', 'http://www.w3.org/2000/svg'))
-            .to.be.true;
+          expect(
+            root.children[3].hasAttr('xmlns', 'http://www.w3.org/2000/svg')
+          ).to.be.true;
         });
 
         it('svg.hasAttr("xmlns", "trololo") should be false', function () {
-          expect(root.content[3].hasAttr('xmlns', 'trololo')).to.be.false;
+          expect(root.children[3].hasAttr('xmlns', 'trololo')).to.be.false;
         });
 
         it('svg.hasAttr("trololo") should be false', function () {
-          expect(root.content[3].hasAttr('trololo')).to.be.false;
+          expect(root.children[3].hasAttr('trololo')).to.be.false;
         });
 
-        it('svg.content[1].hasAttr() should be false', function () {
-          expect(root.content[3].content[1].hasAttr()).to.be.false;
+        it('svg.children[1].hasAttr() should be false', function () {
+          expect(root.children[3].children[1].hasAttr()).to.be.false;
         });
       });
 
       describe('attr()', function () {
         it('svg should have property "attr"', function () {
-          expect(root.content[3]).to.have.property('attr');
+          expect(root.children[3]).to.have.property('attr');
         });
 
         it('svg.attr("xmlns") should be an instance of Object', function () {
-          expect(root.content[3].attr('xmlns')).to.be.an.instanceOf(Object);
+          expect(root.children[3].attr('xmlns')).to.be.an.instanceOf(Object);
         });
 
         it('svg.attr("xmlns", "http://www.w3.org/2000/svg") should be an instance of Object', function () {
           expect(
-            root.content[3].attr('xmlns', 'http://www.w3.org/2000/svg')
+            root.children[3].attr('xmlns', 'http://www.w3.org/2000/svg')
           ).to.be.an.instanceOf(Object);
         });
 
         it('svg.attr("xmlns", "trololo") should be an undefined', function () {
-          expect(root.content[3].attr('xmlns', 'trololo')).to.not.exist;
+          expect(root.children[3].attr('xmlns', 'trololo')).to.not.exist;
         });
 
         it('svg.attr("trololo") should be an undefined', function () {
-          expect(root.content[3].attr('trololo')).to.not.exist;
+          expect(root.children[3].attr('trololo')).to.not.exist;
         });
 
         it('svg.attr() should be undefined', function () {
-          expect(root.content[3].attr()).to.not.exist;
+          expect(root.children[3].attr()).to.not.exist;
         });
       });
 
       describe('removeAttr()', function () {
         it('svg should have property "removeAttr"', function () {
-          expect(root.content[3]).to.have.property('removeAttr');
+          expect(root.children[3]).to.have.property('removeAttr');
         });
 
         it('svg.removeAttr("width") should be true', function () {
-          expect(root.content[3].removeAttr('width')).to.be.true;
+          expect(root.children[3].removeAttr('width')).to.be.true;
 
-          expect(root.content[3].hasAttr('width')).to.be.false;
+          expect(root.children[3].hasAttr('width')).to.be.false;
         });
 
         it('svg.removeAttr("height", "120px") should be true', function () {
-          expect(root.content[3].removeAttr('height', '120px')).to.be.true;
+          expect(root.children[3].removeAttr('height', '120px')).to.be.true;
 
-          expect(root.content[3].hasAttr('height')).to.be.false;
+          expect(root.children[3].hasAttr('height')).to.be.false;
         });
 
         it('svg.removeAttr("x", "1px") should be false', function () {
-          expect(root.content[3].removeAttr('x', '1px')).to.be.false;
+          expect(root.children[3].removeAttr('x', '1px')).to.be.false;
 
-          expect(root.content[3].hasAttr('x')).to.be.true;
+          expect(root.children[3].hasAttr('x')).to.be.true;
         });
 
         it('svg.removeAttr("z") should be false', function () {
-          expect(root.content[3].removeAttr('z')).to.be.false;
+          expect(root.children[3].removeAttr('z')).to.be.false;
         });
 
         it('svg.removeAttr() should be false', function () {
-          expect(root.content[3].removeAttr()).to.be.false;
+          expect(root.children[3].removeAttr()).to.be.false;
         });
       });
 
@@ -298,41 +299,41 @@ describe('svg2js', function () {
         };
 
         it('svg should have property "addAttr"', function () {
-          expect(root.content[3]).to.have.property('addAttr');
+          expect(root.children[3]).to.have.property('addAttr');
         });
 
         it('svg.addAttr(attr) should be an instance of Object', function () {
-          expect(root.content[3].addAttr(attr)).to.be.an.instanceOf(Object);
+          expect(root.children[3].addAttr(attr)).to.be.an.instanceOf(Object);
         });
 
-        it('svg.content[1].content[0].addAttr(attr) should be an instance of Object', function () {
+        it('svg.children[1].children[0].addAttr(attr) should be an instance of Object', function () {
           expect(
-            root.content[3].content[1].content[0].addAttr(attr)
+            root.children[3].children[1].children[0].addAttr(attr)
           ).to.be.an.instanceOf(Object);
         });
 
         it('svg.addAttr() should be false', function () {
-          expect(root.content[3].addAttr()).to.be.false;
+          expect(root.children[3].addAttr()).to.be.false;
         });
       });
 
       describe('eachAttr()', function () {
         it('svg should have property "eachAttr"', function () {
-          expect(root.content[3]).to.have.property('eachAttr');
+          expect(root.children[3]).to.have.property('eachAttr');
         });
 
-        it('svg.content[0].eachAttr(function() {}) should be true', function () {
+        it('svg.children[0].eachAttr(function() {}) should be true', function () {
           expect(
-            root.content[3].content[0].eachAttr(function (attr) {
+            root.children[3].children[0].eachAttr(function (attr) {
               attr.value = '1';
             })
           ).to.be.true;
 
-          expect(root.content[3].content[0].attr('type').value).to.equal('1');
+          expect(root.children[3].children[0].attr('type').value).to.equal('1');
         });
 
-        it('svg.content[1].eachAttr(function() {}) should be false', function () {
-          expect(root.content[3].content[1].eachAttr()).to.be.false;
+        it('svg.children[1].eachAttr(function() {}) should be false', function () {
+          expect(root.children[3].children[1].eachAttr()).to.be.false;
         });
       });
     });