diff --git a/lib/svgo/jsAPI.js b/lib/svgo/jsAPI.js
index 6355b9023..bbc99fb4b 100644
--- a/lib/svgo/jsAPI.js
+++ b/lib/svgo/jsAPI.js
@@ -22,7 +22,7 @@ JSAPI.prototype.clone = function() {
     var nodeData = {};
 
     Object.keys(node).forEach(function(key) {
-        if (key != 'content') {
+        if (key !== 'content') {
             nodeData[key] = node[key];
         }
     });
@@ -72,7 +72,7 @@ JSAPI.prototype.isElem = function(param) {
  */
 JSAPI.prototype.renameElem = function(name) {
 
-    if (typeof name == 'string' && name != '')
+    if (name && typeof name === 'string')
         this.elem = this.local = name;
 
     return this;
@@ -198,16 +198,16 @@ JSAPI.prototype.renameElem = function(name) {
 /**
  * Add attribute.
  *
- * @param {Object} attr attribute object
- * @return {Object} created attribute
+ * @param {Object} [attr={}] attribute object
+ * @return {Object|Boolean} created attribute or false if no attr was passed in
  */
  JSAPI.prototype.addAttr = function(attr) {
+    attr = attr || {};
 
-    if (!attr ||
-        (attr && attr.name === undefined) ||
-        (attr && attr.value === undefined) ||
-        (attr && attr.prefix === undefined) ||
-        (attr && attr.local === undefined)
+    if (attr.name === undefined ||
+        attr.value === undefined ||
+        attr.prefix === undefined ||
+        attr.local === undefined
     ) return false;
 
     this.attrs = this.attrs || {};