Update README.md

README.md

@@ -4,7 +4,20 @@
 
 ![logo](./ogp_dark.png)
 
+AWS API Response Builder is a library that simplifies the process of constructing responses in a type-safe manner when using API Gateway proxy integration with AWS Lambda functions.
+
+## Features
+
+- Flexible configuration of response status code, headers, and body.
+- Fluent interface for writing readable code using method chaining.
+- Generic type parameters to specify the types of response body and headers.
+- Default response of Internal Server Error for easy error handling.
+- Default headers for CORS: `Access-Control-Allow-Origin` and `Access-Control-Allow-Credentials`.
+
 ## Getting started
+
+Install the library using npm:
+
 ```
 $ npm i -S aws-api-responsebuilder
 ```
@@ -29,14 +42,44 @@ console.log(ResponseBuilder.getResponse())
   body: '{"message":"Invalid Request","code":"invalid_request"}' }
 ```
 
-## TypeScript
+### TypeScript
+
+
+```typescript
+import { ResponseFactory } from 'aws-api-responsebuilder';
+
+// Build the response
+const response = ResponseFactory.init<MyResponseBody, MyResponseHeaders>()
+  .setStatusCode(200)
+  .updateHeader('Content-Type', 'application/json')
+  .setBody({ message: 'Success' })
+  .getResponse();
 
+// Use it in the AWS Lambda function handler
+export const handler: APIGatewayProxyHandler = async (event, context) => {
+  // Return the response
+  return response;
+};
 ```
-const ResponseBuilder = ResponseFactory.init<string, {"x-header1": string}>()
-
-ResponseBuilder
-  .putHeaders({
-      "x-header1": "",
-  })
-  .setBody('message')
-```
+
+## API Reference
+
+### ResponseFactory.init<Body, Headers>()
+
+Initializes a `ResponseBuilder` object.
+
+- `Body`: Specifies the type of the response body. Default is `any`.
+- `Headers`: Specifies the type of the response headers. Default is `APIGatewayResponseHeaders`.
+
+### ResponseBuilder Methods
+
+- `setStatusCode(code: number)`: Sets the status code of the response.
+- `updateHeader(key: string, value: string)`: Updates the response headers with the specified key and value. If the header doesn't exist, a new header is created.
+- `putHeaders(headers: Headers)`: Sets the response headers in bulk.
+- `setBody(body?: Body)`: Sets the body of the response. If the body is not a string, it is converted to JSON. If no body is specified, the `unsetBody()` method is called.
+- `unsetBody()`: Removes the body from the response.
+- `getResponse()`: Returns the constructed response as `APIGatewayProxyResult` type.
+
+## License
+
+This library is released under the MIT License.