diff --git a/dist/index.js b/dist/index.js
index d81c2849..3e5f7fa6 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -3,7 +3,7 @@ const esprima = require('esprima');
 const escodegen = require('escodegen');
 const Obfuscator_1 = require('./src/Obfuscator');
 class JavaScriptObfuscator {
-    static obfuscate(sourceCode, customOptions = {}) {
+    static obfuscate(sourceCode, customOptions) {
         let astTree = esprima.parse(sourceCode), options = Object.assign(JavaScriptObfuscator.defaultOptions, customOptions), obfuscator = new Obfuscator_1.Obfuscator(options);
         obfuscator.obfuscateNode(astTree);
         return JavaScriptObfuscator.generateCode(astTree, options);
diff --git a/index.ts b/index.ts
index 1c0dae58..55234620 100644
--- a/index.ts
+++ b/index.ts
@@ -31,7 +31,7 @@ class JavaScriptObfuscator {
      * @param sourceCode
      * @param customOptions
      */
-    public static obfuscate (sourceCode: string, customOptions: any = {}): string {
+    public static obfuscate (sourceCode: string, customOptions?: any): string {
         let astTree: IProgramNode = esprima.parse(sourceCode),
             options: any = Object.assign(JavaScriptObfuscator.defaultOptions, customOptions),
             obfuscator: Obfuscator = new Obfuscator(options);