chore: use async syntax instead of callbacks (#80)

* chore: use async/await instead of callbacks

Author: WajeehZantout

.prettierrc

@@ -1,4 +1,4 @@
 {
-  singleQuote: true,
-  trailingComma: "es5"
+  "singleQuote": true,
+  "trailingComma": "es5"
 }

README.md

@@ -48,7 +48,7 @@ Ignoring the scheduling event, you can see here that we're setting up a function
 
 #### 2. Create your function
 
-This starter kit's Hello World function (which you will of course get rid of) can be found at [`./src/hello.js`](./src/hello.js). There you can see a basic function that's intended to work in conjunction with API Gateway (i.e., it is web-accessible). Like most Serverless functions, the `hello` function accepts an event, context, and callback. When your function is completed, you execute the callback with your response. (This is all basic Serverless; if you've never used it, be sure to read through [their docs](https://serverless.com/framework/docs/).
+This starter kit's Hello World function (which you will of course get rid of) can be found at [`./src/hello.js`](./src/hello.js). There you can see a basic function that's intended to work in conjunction with API Gateway (i.e., it is web-accessible). Like most Serverless functions, the `hello` function is asynchronous and accepts an event & context. (This is all basic Serverless; if you've never used it, be sure to read through [their docs](https://serverless.com/framework/docs/).
 
 ---
 

src/__snapshots__/hello.test.js.snap

@@ -1,21 +1,8 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`hello executes as expected 1`] = `
-[MockFunction] {
-  "calls": Array [
-    Array [
-      null,
-      Object {
-        "body": "{\\"message\\":\\"Go Serverless! Your function executed successfully!\\",\\"input\\":{}}",
-        "statusCode": 200,
-      },
-    ],
-  ],
-  "results": Array [
-    Object {
-      "type": "return",
-      "value": undefined,
-    },
-  ],
+Object {
+  "body": "{\\"message\\":\\"Go Serverless! Your function executed successfully!\\",\\"input\\":{}}",
+  "statusCode": 200,
 }
 `;

src/hello-ts.ts

@@ -1,21 +1,14 @@
 import { successResponse, runWarm } from './utils';
 
-const helloTs: AWSLambda.Handler = (
-  event: AWSLambda.APIGatewayEvent,
-  _context,
-  callback
-) => {
+const helloTs: Function = async (event: AWSLambda.APIGatewayEvent) => {
   // successResponse handles wrapping the response in an API Gateway friendly
   // format (see other responses, including CORS, in `./utils/lambda-response.js)
   const response = successResponse({
     message: 'Go Serverless! Your function executed successfully!',
     input: event,
   });
 
-  callback(null, response);
-
-  // Use this code if you don't use the http event with the LAMBDA-PROXY integration
-  // callback(null, { message: 'Go Serverless v1.0! Your function executed successfully!', event });
+  return response;
 };
 
 // runWarm function handles pings from the scheduler so you don't

src/hello.js

@@ -1,17 +1,14 @@
 import { successResponse, runWarm } from './utils';
 
-const hello = (event, context, callback) => {
+const hello = async event => {
   // successResponse handles wrapping the response in an API Gateway friendly
   // format (see other responses, including CORS, in `./utils/lambda-response.js)
   const response = successResponse({
     message: 'Go Serverless! Your function executed successfully!',
     input: event,
   });
 
-  callback(null, response);
-
-  // Use this code if you don't use the http event with the LAMBDA-PROXY integration
-  // callback(null, { message: 'Go Serverless v1.0! Your function executed successfully!', event });
+  return response;
 };
 
 // runWarm function handles pings from the scheduler so you don't

src/hello.test.js

@@ -1,10 +1,8 @@
 import hello from './hello';
 
 describe('hello', () => {
-  it('executes as expected', () => {
-    const cb = jest.fn();
-    hello({}, {}, cb);
-    expect(cb).toBeCalled();
-    expect(cb).toMatchSnapshot();
+  it('executes as expected', async () => {
+    const response = await hello({});
+    expect(response).toMatchSnapshot();
   });
 });

src/types/index.ts

@@ -1,15 +1,14 @@
-const runWarm = (lambdaFunc: AWSLambda.Handler): AWSLambda.Handler => (
+const runWarm = (lambdaFunc: Function): AWSLambda.Handler => async (
   event,
-  context,
-  callback
+  context
 ) => {
   // Detect the keep-alive ping from CloudWatch and exit early. This keeps our
   // lambda function running hot.
   if (event.source === 'serverless-plugin-warmup') {
-    return callback(null, 'pinged');
+    return 'pinged';
   }
 
-  return lambdaFunc(event, context, callback);
+  return lambdaFunc(event, context);
 };
 
 export default runWarm;