diff --git a/lib/nodes.js b/lib/nodes.js
index da3d18bc..4a8f3b6e 100644
--- a/lib/nodes.js
+++ b/lib/nodes.js
@@ -141,9 +141,12 @@
         if (func(child) === false) {
           return false;
         }
-        return child instanceof Base && (crossScope || !(child instanceof Code)) ? child.traverseChildren(crossScope, func) : undefined;
+        return crossScope || !(child instanceof Code) ? child.traverseChildren(crossScope, func) : undefined;
       });
     };
+    Base.prototype.invert = function() {
+      return new Op('!', this);
+    };
     Base.prototype.children = [];
     Base.prototype.unwrap = THIS;
     Base.prototype.isStatement = NO;
@@ -1271,13 +1274,7 @@
     While = (function() {
       return function While(condition, opts) {
         While.__super__.constructor.call(this);
-        if (((opts != null) ? opts.invert : undefined)) {
-          if (condition instanceof Op) {
-            condition = new Parens(condition);
-          }
-          condition = new Op('!', condition);
-        }
-        this.condition = condition;
+        this.condition = ((opts != null) ? opts.invert : undefined) ? condition.invert() : condition;
         this.guard = ((opts != null) ? opts.guard : undefined);
         return this;
       };
@@ -1362,10 +1359,6 @@
     Op.prototype.isUnary = function() {
       return !this.second;
     };
-    Op.prototype.isInvertible = function() {
-      var _ref2;
-      return ('===' === (_ref2 = this.operator) || '!==' === _ref2);
-    };
     Op.prototype.isComplex = function() {
       return this.operator !== '!' || this.first.isComplex();
     };
@@ -1377,7 +1370,11 @@
       return include(this.CHAINABLE, this.operator);
     };
     Op.prototype.invert = function() {
-      return (this.operator = this.INVERSIONS[this.operator]);
+      var _ref2;
+      if (('===' === (_ref2 = this.operator) || '!==' === _ref2)) {
+        this.operator = this.INVERSIONS[this.operator];
+        return this;
+      } else       return this.second ? new Parens(this).invert() : Op.__super__.invert.call(this);
     };
     Op.prototype.toString = function(idt) {
       return Op.__super__.toString.call(this, idt, this.constructor.name + ' ' + this.operator);
@@ -1780,22 +1777,10 @@
   exports.If = (function() {
     If = (function() {
       return function If(condition, _arg, _arg2) {
-        var op;
         this.tags = _arg2;
         this.body = _arg;
         this.tags || (this.tags = {});
-        if (this.tags.invert) {
-          op = condition instanceof Op;
-          if (op && condition.isInvertible()) {
-            condition.invert();
-          } else {
-            if (op && !condition.isUnary()) {
-              condition = new Parens(condition);
-            }
-            condition = new Op('!', condition);
-          }
-        }
-        this.condition = condition;
+        this.condition = this.tags.invert ? condition.invert() : condition;
         this.elseBody = null;
         this.isChain = false;
         return this;
diff --git a/src/nodes.coffee b/src/nodes.coffee
index 363b48cc..e677828c 100644
--- a/src/nodes.coffee
+++ b/src/nodes.coffee
@@ -128,10 +128,11 @@ exports.Base = class Base
   traverseChildren: (crossScope, func) ->
     @eachChild (child) ->
       return false if func(child) is false
-      if child instanceof Base and
-         (crossScope or child not instanceof Code)
+      if crossScope or child not instanceof Code
         child.traverseChildren crossScope, func
 
+  invert: -> new Op '!', this
+
   # Default implementations of the common node properties and methods. Nodes
   # will override these with custom logic, if needed.
   children: []
@@ -1103,10 +1104,7 @@ exports.While = class While extends Base
 
   constructor: (condition, opts) ->
     super()
-    if opts?.invert
-      condition = new Parens condition if condition instanceof Op
-      condition = new Op('!', condition)
-    @condition  = condition
+    @condition  = if opts?.invert then condition.invert() else condition
     @guard = opts?.guard
 
   addBody: (body) ->
@@ -1184,9 +1182,6 @@ exports.Op = class Op extends Base
   isUnary: ->
     not @second
 
-  isInvertible: ->
-    @operator in ['===', '!==']
-
   isComplex: -> @operator isnt '!' or @first.isComplex()
 
   isMutator: ->
@@ -1196,7 +1191,13 @@ exports.Op = class Op extends Base
     include(@CHAINABLE, @operator)
 
   invert: ->
-    @operator = @INVERSIONS[@operator]
+    if @operator in ['===', '!==']
+      @operator = @INVERSIONS[@operator]
+      this
+    else if @second
+      new Parens(this).invert()
+    else
+      super()
 
   toString: (idt) ->
     super(idt, @constructor.name + ' ' + @operator)
@@ -1517,14 +1518,7 @@ exports.If = class If extends Base
 
   constructor: (condition, @body, @tags) ->
     @tags or= {}
-    if @tags.invert
-      op = condition instanceof Op
-      if op and condition.isInvertible()
-        condition.invert()
-      else
-        condition = new Parens condition if op and not condition.isUnary()
-        condition = new Op '!', condition
-    @condition = condition
+    @condition = if @tags.invert then condition.invert() else condition
     @elseBody  = null
     @isChain   = false