Svelte Capacitor Recipe

Small recipe to create a svelte kit app and package it for mobile (ios/android) with capacitor.

🚀 Create svelte kit project

See https://kit.svelte.dev/docs/creating-a-project

npm create svelte@latest my-app
# Pick "skeleton project"
# Typescript and prettier are also pretty cool

cd my-app
npm install
npm run dev

🤓 Program something

Program your app. Minimal example: https://gist.github.com/bersling/33dd5afe071b3aa6b93a35d42b2afabc .

📁 Switch to SSG (=Static Site Generation)

(1) Install the static adapter

npm install @sveltejs/adapter-static

(2) Use the following svelte.config.js:

import adapter from '@sveltejs/adapter-static';
import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';

/** @type {import('@sveltejs/kit').Config} */
const config = {
    // Consult https://kit.svelte.dev/docs/integrations#preprocessors
    // for more information about preprocessors
    preprocess: vitePreprocess(),

    kit: {
        // adapter-auto only supports some environments, see https://kit.svelte.dev/docs/adapter-auto for a list.
        // If your environment is not supported or you settled on a specific environment, switch out the adapter.
        // See https://kit.svelte.dev/docs/adapters for more information about adapters.
        adapter: adapter({
            pages: 'dist',
            assets: 'dist',
            fallback: null,
            precompress: false,
            strict: true
        })
    }
};

export default config;

(3) Create a +layout.ts file under ./src/routes/ with content:

export const prerender = true;

Verify your setup with npm run build, which should succeed and create a dist folder. Also, add dist to your .gitignore.

⚡ Set up capacitor

Add capacitor to project, see https://capacitorjs.com/

npm i @capacitor/core @capacitor/android @capacitor/ios
npm i -D @capacitor/cli
npx cap init

🤖 Set up android app

First, run

npx cap add android

Every time you make code changes, you then run npm run build && npx cap sync to sync the changes to the android project. Execute that step now.

Install Android Studio if you haven't and open the project with npx cap open android.

 Set up ios app

First, run

npx cap add ios

Then run

npx cap open ios

Don't forget to run npm run build && npx cap sync on code changes.

Select a target device to test, or select build for any device and then hit "archive" to ship.

😢 Optimize

Take from here what's helpful to you.

Fix viewport

Change meta tag in app.html to

        <meta name="viewport"
            content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0, viewport-fit=cover" />

Prevents stuff like zooming in on double click.

Prevent users from doing unwanted things

In app.html add a style tag with the content

        <style>
            * {
                box-sizing: border-box;

                /* disable text selection (svg icons are also text...) */
                -webkit-user-select: none;
                /* Safari */
                -ms-user-select: none;
                /* IE 10 and IE 11 */
                user-select: none;
                /* Standard syntax */

                /* preventing the long press context menu, https://stackoverflow.com/a/56866766/3022127 */
                -webkit-touch-callout: none !important;
                -webkit-user-select: none !important;

                /* preventing iOS tap highlight */
                -webkit-tap-highlight-color: transparent;

                /* Disable browser handling of all panning and zooming gestures, except for regular scrolling */
                touch-action: pan-y;
            }
        </style>

Fix App Specific Oddities

In the app from above, on iOS it just looked weird. The font size calculation seems to be off. So here's a version that fixes this on iOS and shows you capacitors native feature: https://gist.github.com/bersling/ebe95f7918b3169b3d36b0b13272daf9 .

💡 Comprehensive Examples

Svelte Puzzle

Svelte Puzzle (https://github.com/bersling/sveltepuzzle) is a puzzle game built with Svelte for SvelteHack 2023. It shows how Svelte can be used together with Capacitor to build mobile apps for iOS and Android.

Toddler & Preschool Games

Toddler & Preschool Games is a full game I've developed with this setup and released to the app stores:

• Web: https://toddler-games.com/
• Android: https://play.google.com/store/apps/details?id=com.toddlergames.drn
• iOS: https://apps.apple.com/us/app/toddler-preschool-games/id6447790341

I didn't open source the code yet, it's pretty similar to Svelte Puzzle from above though.