adapter-cloudflare-workers

SvelteKit adapter that creates a Cloudflare Workers site using a function for dynamic server rendering.

This is very experimental; the adapter API isn't at all fleshed out, and things will definitely change.

Comparisons

• adapter-cloudflare – supports all SvelteKit features; builds for Cloudflare Pages
• adapter-cloudflare-workers – supports all SvelteKit features; builds for Cloudflare Workers
• adapter-static – only produces client-side static assets; compatible with Cloudflare Pages

Note: Cloudflare Pages' new Workers integration is currently in beta.
Compared to adapter-cloudflare-workers, this adapter will be the preferred approach for most users since building on top of Pages unlocks automatic builds and deploys, preview deployments, instant rollbacks, etc.
From SvelteKit's perspective, there is no difference and no functionality loss when migrating to/from the Workers and the Pages adapters.

Usage

Install with npm i -D @sveltejs/adapter-cloudflare-workers@next, then add the adapter to your svelte.config.js:

import adapter from '@sveltejs/adapter-cloudflare-workers';

export default {
    kit: {
        target: '#svelte',
        adapter: adapter()
    }
};

Basic Configuration

You will need Wrangler installed on your system

This adapter expects to find a wrangler.toml file in the project root. It will determine where to write static assets and the worker based on the site.bucket and site.entry-point settings.

Generate this file using wrangler from your project directory

wrangler init --site my-site-name

Now you should get some details from Cloudflare. You should get your:

1. Account ID
2. And your Zone-ID (Optional)

Get them by visiting your Cloudflare-Dashboard and click on any domain. There, you can scroll down and on the left, you can see your details under API.

Then configure your sites build directory and your account-details in the config file:

account_id = 'YOUR ACCOUNT_ID'
zone_id    = 'YOUR ZONE_ID' # optional, if you don't specify this a workers.dev subdomain will be used.
site = {bucket = "./build", entry-point = "./workers-site"}

type = "javascript"

[build]
# Assume it's already been built. You can make this "npm run build" to ensure a build before publishing
command = ""

[build.upload]
format = "service-worker"

It's recommended that you add the build and workers-site folders (or whichever other folders you specify) to your .gitignore.

Now, log in with wrangler:

wrangler login

Build your project and publish it:

npm run build && wrangler publish

You are done!

More info on configuring a cloudflare worker site can be found here

Advanced Configuration

esbuild

As an escape hatch, you may optionally specify a function which will receive the final esbuild options generated by this adapter and returns a modified esbuild configuration. The result of this function will be passed as-is to esbuild. The function can be async.

For example, you may wish to add a plugin:

adapterCfw({
    esbuild(options) {
        return {
            ...options,
            plugins: []
        };
    }
});

The default options for this version are as follows:

const options = {
    entryPoints: ['.svelte-kit/cloudflare-workers/entry.js'],
    outfile: `${entrypoint}/index.js`,
    bundle: true,
    target: 'es2020',
    platform: 'browser'
};

Changelog

The Changelog for this package is available on GitHub.