diff --git a/index.ts b/index.ts
index d8460a3..7b5e259 100644
--- a/index.ts
+++ b/index.ts
@@ -62,13 +62,10 @@ export enum TypeKind {
     UNION
 }
 
-export interface TypeModel {
-    typeKind: TypeKind;
+export type TypeModel = BasicType | ArrayType | UnionType;
 
-}
-
-export interface BasicType extends TypeModel {
-    //typeName:string
+export interface BasicType {
+    typeKind: TypeKind.BASIC;
     nameSpace: string;
     basicName: string;
     typeName: string;
@@ -76,13 +73,15 @@ export interface BasicType extends TypeModel {
     modulePath: string;
 }
 
-export interface ArrayType extends TypeModel {
+export interface ArrayType {
+    typeKind: TypeKind.ARRAY;
     base: TypeModel;
 }
 
-export type Arg = string|number|boolean;
+export type Arg = string | number | boolean;
 
-export interface UnionType extends TypeModel {
+export interface UnionType {
+    typeKind: TypeKind.UNION;
     options: TypeModel[];
 }
 
@@ -174,4 +173,4 @@ export function classDecl(name: string, isInteface: boolean): ClassModel {
 
 export function parseStruct(content: string, modules: {[path: string]: Module}, mpth: string): Module {
     return tsStructureParser.parseStruct(content, modules, mpth);
-}
\ No newline at end of file
+}