diff --git a/README.md b/README.md
index 460f926..b4778b3 100644
--- a/README.md
+++ b/README.md
@@ -21,17 +21,32 @@ gitDiffParser.parse(gitDiffText);
 ### API
 
 ```ts
-export interface Change {
+export interface InsertChange {
+    type: 'insert';
     content: string;
-    type: 'insert' | 'delete' | 'normal';
-    isInsert?: boolean;
-    isDelete?: boolean;
-    isNormal?: boolean;
-    lineNumber?: number;
-    oldLineNumber?: number;
-    newLineNumber?: number;
+    lineNumber: number;
+    isInsert: true;
 }
 
+export interface DeleteChange {
+    type: 'delete';
+    content: string;
+    lineNumber: number;
+    isDelete: true;
+}
+
+export interface NormalChange {
+    type: 'normal';
+    content: string;
+    isNormal: true;
+    oldLineNumber: number;
+    newLineNumber: number;
+}
+
+export type Change = InsertChange | DeleteChange | NormalChange;
+
+export type ChangeType = Change['type'];
+
 export interface Hunk {
     content: string;
     oldStart: number;
@@ -41,6 +56,8 @@ export interface Hunk {
     changes: Change[];
 }
 
+export type FileType = 'add' | 'delete' | 'modify' | 'rename' | 'copy';
+
 export interface File {
     hunks: Hunk[];
     oldEndingNewLine: boolean;
@@ -53,10 +70,10 @@ export interface File {
     oldPath: string;
     newPath: string;
     isBinary?: boolean;
-    type: 'add' | 'delete' | 'modify' ｜ 'rename';
+    type: FileType;
 }
 
-export default {
-    parse(source: string): File[];
-};
+export function parse(source: string): File[];
+
+export as namespace gitDiffParser;
 ```
diff --git a/index.d.ts b/index.d.ts
index ba78dd7..11d6842 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -1,5 +1,3 @@
-export type ChangeType = 'insert' | 'delete' | 'normal';
-
 export interface InsertChange {
     type: 'insert';
     content: string;
@@ -24,6 +22,8 @@ export interface NormalChange {
 
 export type Change = InsertChange | DeleteChange | NormalChange;
 
+export type ChangeType = Change['type'];
+
 export interface Hunk {
     content: string;
     oldStart: number;
@@ -50,6 +50,6 @@ export interface File {
     type: FileType;
 }
 
-export default {
-    parse(source: string): File[];
-};
+export function parse(source: string): File[];
+
+export as namespace gitDiffParser;