Utility classes with state now are non-static

src/JavaScriptObfuscatorInternal.ts

@@ -59,7 +59,7 @@ export class JavaScriptObfuscatorInternal implements IJavaScriptObfuscator {
      */
     public obfuscate (sourceCode: string): IObfuscationResult {
         // parse AST tree
-        const astTree: ESTree.Program = esprima.parse(sourceCode, { loc: this.options.sourceMap });
+        const astTree: ESTree.Program = this.parseCode(sourceCode);
 
         // obfuscate AST tree
         const obfuscatedAstTree: ESTree.Program = this.obfuscator.obfuscateAstTree(astTree);
@@ -70,6 +70,16 @@ export class JavaScriptObfuscatorInternal implements IJavaScriptObfuscator {
         return this.getObfuscationResult(generatorOutput);
     }
 
+    /**
+     * @param sourceCode
+     * @return {ESTree.Program}
+     */
+    private parseCode (sourceCode: string): ESTree.Program {
+        return esprima.parse(sourceCode, {
+            loc: this.options.sourceMap
+        });
+    }
+
     /**
      * @param sourceCode
      * @param astTree