feat: added lambdaRegion option to config options

this will let the consumer decide which region to invoke on the target function
if trying network request across regions, the user must currently pass the entire Lambda class in just to configure this one variable

src/adapters/lambda-invocation.ts

@@ -13,9 +13,15 @@ import { AbortController } from '@aws-sdk/abort-controller';
 const lambdaInvocationAdapter: AlphaAdapter = async (config) => {
   const LambdaClass = config.Lambda || Lambda;
   const lambdaOptions: LambdaClientConfig = {
+    region: config.lambdaRegion,
     endpoint: config.lambdaEndpoint || process.env.LAMBDA_ENDPOINT,
   };
 
+  if (config.lambdaRegion) {
+    // Allow the region to be controlled via config
+    lambdaOptions.region = config.lambdaRegion;
+  }
+
   if (config.timeout) {
     // Set some low level HTTP client timeout options
     // so that the system level resources will be

src/types.ts

@@ -1,5 +1,5 @@
 import type { AxiosPromise, AxiosRequestConfig, AxiosResponse, InternalAxiosRequestConfig } from 'axios';
-import type { Lambda } from '@aws-sdk/client-lambda';
+import type { Lambda, LambdaClientConfig } from '@aws-sdk/client-lambda';
 import type { Context, Handler } from 'aws-lambda';
 import { SignatureV4CryptoInit, SignatureV4Init } from '@aws-sdk/signature-v4';
 
@@ -26,6 +26,10 @@ export interface AlphaOptions<D = any> extends AxiosRequestConfig<D> {
    * (Optional) The AWS endpoint to use when invoking the target Lambda function.
    */
   lambdaEndpoint?: string;
+  /**
+   * (Optional) The AWS region to use when invoking the target Lambda function.
+   */
+  lambdaRegion?: LambdaClientConfig['region'];
   Lambda?: typeof Lambda;
 }
 

test/lambda-invocation.test.ts

@@ -524,3 +524,24 @@ test('lambdaEndpoint config option is provided to the Lambda client', async () =
 
   expect(FakeLambda).toHaveBeenCalledWith({ endpoint: 'http://test-endpoint' });
 });
+
+test('lambdaRegion config option is provided to the Lambda client', async () => {
+  const alpha = new Alpha('lambda://test-function', {
+    lambdaRegion: 'ap-southeast-2',
+    Lambda: FakeLambda,
+  });
+  createResponse(mockLambda, {
+    StatusCode: 200,
+    Payload: {
+      body: 'test',
+      statusCode: 200,
+    },
+  });
+
+  const response = await alpha.get('/test');
+
+  expect(response.data).toBe('test');
+  expect(response.status).toBe(200);
+
+  expect(FakeLambda).toHaveBeenCalledWith({ region: 'ap-southeast-2' });
+});