Added tests for issue https://github.com/javascript-obfuscator/javascript-obfuscator/issues/297

src/node/NodeGuards.ts

@@ -120,6 +120,16 @@ export class NodeGuards {
         return node.type === NodeType.ExpressionStatement;
     }
 
+    /**
+     * @param {Node} node
+     * @returns {boolean}
+     */
+    public static isFunctionNode(node: ESTree.Node): node is ESTree.Function {
+        return NodeGuards.isFunctionDeclarationNode(node) ||
+            NodeGuards.isFunctionExpressionNode(node) ||
+            NodeGuards.isArrowFunctionExpressionNode(node);
+    }
+
     /**
      * @param {Node} node
      * @returns {boolean}