Svelte


⏱ This tutorial is an introductory walkthrough of creating a Svelte app on Begin. It should take less than 5 minutes.

Introduction

Hello there, Beginner!

This tutorial walks through setting up a Svelte app running on Begin. Svelte is a new approach to building user interfaces; unlike many frontend frameworks that do the bulk of their work in the browser (like React and Vue), Svelte shifts that work into a compile step that happens when you build your app. Today you'll learn how to create a Svelte app powered by Begin HTTP functions.

Prerequisites

You will need to have git and Node.js installed to your local computer to follow along with this tutorial. (Learn more about installing git and installing Node.js.)

You'll also need a GitHub account. (Learn more about signing up with GitHub.)

This tutorial also assumes some familiarity with such things as:

  • Text editors
  • Terminal / CLI
  • Git and version control
  • General software development using JavaScript

You do not need to be an expert in any of these things in order to follow along and make a Svelte app in Begin!.


Getting started

Create your Svelte app

First, click the Deploy to Begin button below. This starts the process of authorizing Begin with your GitHub account. (You may be prompted to log into GitHub, and/or be asked to create a Begin username.)

Deploy to Begin

Name your app & repo

You'll then be prompted to name your new app and repository – this is optional, feel free to use the default app and repo name if you like!

Note: your Begin app name and repository name cannot be changed later.

Name your Begin app and repo

Once you've clicked the Create... button, Begin will spin up your new project on GitHub (under github.com/{your GH username}/{your repo name}).

By default your Begin app repo is created as a public GitHub repo; it can be set to private by granting Begin additional permissions from this screen (or later from the Settings screen found in the left nav of your Begin app).


Your first deploy

After creating your app, you'll be taken to its Activity stream. Welcome to the main backend interface of your Begin app!

Begin Activity view

From the Activity view, you'll be able to watch your app build & deploy in real-time. Any time you push to master, you'll see a new build get kicked off in Begin.

Each build undergoes a number of predefined build steps (learn more about build steps here); these build steps may install your app's dependencies (install), check your code's syntax for issues (lint), generate any files or assets needed to run your app (build), and/or run an automated test suite (test).

If no build steps fail, then the build containing your latest commit to master is automatically deployed to your staging environment.

Go ahead and click the Staging link in the upper left corner of your left nav to open your new app's staging URL. You should now see your basic Svelte app:

Svelte

πŸ’‘ Learn more! Head here to dig deeper into covers build pipelines, git tagging, and more.


Make your first commit

If you'd like to jump right into making your first commit and running your first build, click the Edit on GitHub button. This will open your app's code in GitHub and allow you to make a quick change.

Begin activity

Look for this code, and try changing the text of the h3 tag and the color of the h1 tag:

// Customize your site by changing the color of the h1
<script>
  import { onMount } from 'svelte'
  export let name;
  export let message;
  onMount(async () => {
    let data = await (await fetch('/api')).json()
    message = data.msg
    console.log('MESSAGE: ', message)
  })
</script>

<main>
  <h1>Hello {name}!</h1>
  <h2>{message}</h2>
  <h3>Change me!</h3> // <-- Change text!
  <p>Visit the <a href="https://svelte.dev/tutorial">Svelte tutorial</a> to learn how to build Svelte apps.</p>
</main>

<style>
  main {
    text-align: center;
    padding: 1em;
    max-width: 240px;
    margin: 0 auto;
  }

  h1 {
    color: #ff3e00; // <-- change color!
    text-transform: uppercase;
    font-size: 4em;
    font-weight: 100;
  }

  @media (min-width: 640px) {
    main {
      max-width: none;
    }
  }
</style>

Click the commit changes button on GitHub, and head back to your Activity view to watch it build.

When it's done, don't forget to see your changes live in your staging environment!


Get set up locally

Next let's get your new site running in your local environment (i.e. the computer you work on).

First, head to your GitHub repo (from the first card in your Activity, or from the left nav). Find the clone or download button and copy the git URL.

Then head to your terminal and clone your repo to your local filesystem.

git clone https://github.com/your-github-username/your-new-begin-app.git

Once you've got your project cloned on your local machine, cd into the project directory, install your dependencies, and start the local dev server:

cd your-new-begin-app
npm install
npm run dev

You should see a localhost link in your terminal – go ahead and visit that in your browser.

That's all you need to do preview your changes locally before pushing them to staging!


Project structure

Now that your app is live on staging and running locally, let's take a quick look into how the project itself is structured so you'll know your way around. Here are the key folders in the source tree of your Svelte app:

.
β”œβ”€β”€ public/
β”œβ”€β”€ src/
β”‚   β”œβ”€β”€ http/
β”‚   β”‚   └── get-api/
β”‚   β”œβ”€β”€ App.svelte
β”‚   └── main.mjs
└── rollup.config.js

Let's go over each of these directories and how you may use them:

public/

The public directory is where you'll add images and any other static assets or files you want to make publicly accessible in your app.

Each time your app deploys, the contents of this folder will automatically be published to your app's static asset bucket on S3 and Begin's CDN.

This is also where your component-level CSS & JS are bundled, as well as your app's global CSS, which affects the entirety of your app's styling.

Exercise caution! The full contents of this folder will be copied with each deploy, overwriting any existing files with the same name.

src/http/get-api/

The cloud function that handles requests to your site is found at src/http/get-api/.

Some Begin apps are inert static web sites – but not this one. Your Svelte app is built on a small, fast, individually executing cloud function that handles your HTTP requests and responses. (We call those HTTP functions, for short.)

The HTTP function that handles requests to GET /api is found in src/http/get-api/.

In the next section we will go more in-depth about how to provision HTTP functions in your Svelte app.

πŸ’‘ Learn more! Head here to dig deeper into HTTP functions in Begin apps.

src/main.mjs

The main entry point for your Svelte app, src/main.js imports your App.svelte file (your root app component). In this example, we initialize your app to document.body and pass it a prop to demonstrate how props can be passed along to different components inside of your app.

src/App.svelte

src/App.svelte is what's referred to as a single file component – it contains all of the code needed to display your frontend. The opening <script> tag contains JavaScript, and in this example it receives in props from src/main.js:

<script>
  import { onMount } from 'svelte'
  export let name;
  export let message;
  onMount(async () => {
    let data = await (await fetch('/api')).json()
    message = data.msg
    console.log('MESSAGE: ', message)
  })
</script>

Right below the <script> tag we have a section for our HTML – <main> – which can render variables from your script tag inside {curly brackets}:

<main>
  <h1>Hello {name}!</h1>
  <h2>{message}</h2>
  <h3>Change me!</h3>
  <p>Visit the <a href="https://svelte.dev/tutorial">Svelte tutorial</a> to learn how to build Svelte apps.</p>
</main>

Lastly, at the bottom of src/App.svelte we have a <style> tag, which contains all the CSS for this specific component.

rollup.config.js

Rollup is a module bundler for JavaScript which compiles small pieces of code into something larger and more complex, such as a library or application. It allows us to use ES modules import syntax so that we may create component-based applications. This config file bundles all of your component-level CSS and JS into the public directory.


Using API endpoints

Extending your Svelte app with HTTP functions may be why you're here, right? Let's take a look at how all this works.

Let's start with the src/App.svelte code inside <script> tag found below. When the component renders initially into a page or "mounts", we're able to use what's called a lifecycle method called onMount, which is provided by the Svelte framework. Inside this onMount handler we fetch data from src/http/get-api/ and then set the variable named message with the returned data. We're now able to pass this variable into our HTML as props so that it displays a message from our HTTP function. Not bad, right?

// src/App.svelte

// JavaScript
<script>
  import { onMount } from 'svelte'
  export let name;
  export let message;
  onMount(async () => {
    let data = await (await fetch('/api')).json()
    message = data.msg
    console.log('MESSAGE: ', message)
  })
</script>

// HTML
<main>
  <h1>Hello {name}!</h1>
  <h2>{message}</h2>
  <h3>Change me!</h3>
  <p>Visit the <a href="https://svelte.dev/tutorial">Svelte tutorial</a> to learn how to build Svelte apps.</p>
</main>

This is just one small example of how using a live API endpoint powered by an HTTP function can make your Svelte app dynamic. Just think of all the things you can build this way!


Deploy your site

While not required, it's always a good idea to lint and run tests before pushing just to make sure you catch any errors:

npm run lint
npm t

Everything set? Now let's push this commit (and deploy the build to staging):

git add -A
git commit -am 'Just customizing my Begin site!'
git push origin master

Head on back to Begin and open your staging URL once your build is complete. Looking good? Excellent!

Now let's deploy to production: click the Deploy to production button in the upper left, pick a version, leave an optional message summarizing your changes, and Ship it!

When your next build is done, click the production link in the upper left corner to see the latest release of your app!

✨Tip: You can also deploy to production from your terminal by bumping your npm version (npm version [patch|minor|major] && git push origin) or by cutting a git tag (git tag -a 1.0.0 -m "1.0, here we come" && git push origin --tags)


Congratulations!

You've now got a shiny new Svelte app hosted on Begin – nice work.

Now go show it off – people need to see this thing!


Additional resources