Alexa Skill starter project using AWS Lambda and Typescript

This is a simple starter project for Alexa skills using Typescript.

What is included in the project

Default request handlers

Name
`LaunchRequest`
`SessionEndedRequest`
`System.ExceptionEncountered`
`AMAZON.HelpIntent`
`AMAZON.StopIntent` and `AMAZON.CancelIntent`
`AMAZON.FallbackIntent`

Extra handlers

Name	Description
`HelloWorld`	Triggered when the user says "hello", will answer back with "hello".
`Debug`	Can be placed at the beginning of the request handlers stack and it will print the `handlerInput`. Useful for debugging.

Error handlers

Name	Description
`Unexpected`	Catches `ErrorTypes.Unexpected`, which should be thrown when...something unexpected happens. It will tell the user something unexpected happend, and to try again later.
`Unknown`	Catches all other errors. It will tell the user it didn't understand the command, and to try saying it again (doesn't end session).

Request interceptors

Name	Description
`Localization`	Adds `i18next` localization functions to the `RequestAttributes`.
`Slots`	Parses the slot values, adds additional useful information to them (e.g. if it was an exact match, or if it's ambiguous etc.), and adds them to the `RequestAttributes`. Check the `GetSlotValues` function inside `lambda/custom/lib/helpers.ts` for more details.

Localization strings

Check lambda/custom/lib/strings.ts.

Constants

Including the String keys, so you can have type safety everywhere.

Check lambda/custom/lib/constants.ts.

Helper functions

Many helper functions which should reduce code duplication, and reduce the code needed to do common tasks.

Check lambda/custom/lib/helpers.ts.

Local development

Contains an http server using express, which you can use with ngrok or servo.net during local development. Check the Local development section below for more details.

Scripts

There are a few scripts inside package.json for building and deploying your lambda function using the ask-cli. Check the Developer tasks section below for more details.

Tests

The project contains automated tests using jest. Check the __tests__ folder.

$ npm run test

If you want to include code coverage, run

$ npm run test:coverage

You can also start jest in watch mode:

$ npm run test:watch

Travis CI and Codecov integrations

Pre-requisites

Node.js
Register for an AWS Account
Register for an Amazon Developer Account
Install and Setup ASK CLI

Installation

Install the dependencies

$ npm install

Deployment

ASK CLI will create the skill and the Lambda function for you. The Lambda function will be created in us-east-1 (Northern Virginia) by default.

Navigate to the project's root directory. you should see a file named 'skill.json' there.
Deploy the skill and the Lambda function in one step by running the following command:

$ ask deploy

Local development

In order to develop locally and see your changes reflected instantly, you will need to create an SSH tunnel or expose somehow your local development server. There are several services that allow you to do this, for example ngrok or serveo.net.

Using servo.net

This is the easiest to setup

You need to have an SSH client installed, then simply run

$ ssh -R 80:localhost:3980 serveo.net
Forwarding HTTP traffic from [https://YOUR_URL]
Press g to start a GUI session and ctrl-c to quit.

Once you see the URL, copy it and go to your Skill console.
Open the Endpoint menu and select HTTPS
Under Default Region paste the previous URL you copied.
On the select box choose: My development endpoint is a sub-domain of a domain that has a wildcard certificate from a certificate authority.
You are done! Just run npm start to start the local server and begin testing the skill.

Using ngrok.io

Install ngrok
Run ngrok http 3980
Copy the URL and follow the same steps above from 3 to 6.

Developer tasks

Command	Description
`clean`	Deletes the `dist` folder
`build`	Builds the lambda function and exports it to the `dist` folder
`deploy`	Builds the lambda function and deploys EVERYTHING (skill, model, lambda)
`deploy:lambda`	Builds the lambda function and deploys it (just the lambda function)
`deploy:local`	Deploys the skill details for the local profile, which will update the HTTPS endpoint
`start`	Starts the local `express` server using `nodemon` for local development

To see the actual commands, check package.json.

Also check the ASK CLI Command Reference for more details on using the ASK CLI.

Testing

Taken from the official hello world project.

To test, you need to login to Alexa Developer Console, and enable the "Test" switch on your skill from the "Test" Tab.

Simulate verbal interaction with your skill through the command line (this might take a few moments) using the following example:

 $ ask simulate -l en-US -t "open greeter"

 ✓ Simulation created for simulation id: 4a7a9ed8-94b2-40c0-b3bd-fb63d9887fa7
◡ Waiting for simulation response{
  "status": "SUCCESSFUL",
  ...

Once the "Test" switch is enabled, your skill can be tested on devices associated with the developer account as well. Speak to Alexa from any enabled device, from your browser at echosim.io, or through your Amazon Mobile App and say :
```
Alexa, start hello world
```

Customization