feat: Vite environment API by teemingc · Pull Request #14008 · sveltejs/kit

teemingc · 2025-07-17T05:25:17Z

closes #13692
closes #1712
part of #3535
closes #13739
closes #13357
closes #12637

w.i.p and still has a lot of problems to solve. Needed to open this PR to test installing this from pkg.pr.new since linking locally with pnpm symlinks to the local kit repo. Then, when we try importing kit code from inside an environment, it results in a path which doesn't exist such as /packages/kit/.... Instead, it should probably import from node_modules/@sveltejs/kit/....

This PR adopts the Vite Environment API in kit and changes adapter-cloudflare to use a similar approach to Remix where the user can specify their own worker.js file. Otherwise, we can generate the wrangler config and worker for them. This approach integrates well with vite-plugin-cloudflare and provides users with direct access to the worker script, allowing them to export Durable Objects and add additional handlers.

Thanks to @jamesopstad for #12637 and writing up the Google Doc explaining the Remix and vite-plugin-cloudflare integration. Resources include:

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benmccann · 2025-07-17T22:44:52Z

You probably need to bump the peer dep version on Vite

teemingc · 2025-07-18T02:37:29Z

You probably need to bump the peer dep version on Vite

Thanks! I missed that. Bumped it to 7 because I think 6 is missing some Environment API behaviour around multiple plugins building the app

svelte-docs-bot · 2025-07-18T02:37:52Z

Preview: https://svelte-dev-git-preview-kit-14008-svelte.vercel.app/

teemingc · 2025-09-12T01:56:13Z

Sorry this got paused for such a long time. Took a little time off from this since we were getting remote functions out, then I had some non-SvelteKit work too.

I left a bunch of TODOs in the code which should be enough to get started but I imagine resolving the merge conflicts since remote functions were merged would be step 1. The major goals are in the TODO list from the post at the top of the thread (get it working in cloudflare dev / vite dev). Hopefully I return to this this month if not next.

Giggiux · 2025-10-08T08:53:09Z

I am currently bypassing this issue using the approach defined in this repository, using alchemy.dev. But it adds a bunch of extra dependencies, it requires creating a new Worker script with the Durable Objects that after deployment is attached as a binding to the SvelteKit workers, and most importantly requires an "hack" in dev to send the requests via fetch to the secondary workers dev server, instead of using bindings.

Adding support for the official cloudflare vite plugin, and for websockets would make development with Cloudflare as a target even better with SvelteKit!

Giggiux · 2025-11-22T10:27:55Z

Hey @teemingc is there any way we can help in moving this PR forward?
I could try and spend some time on it, but I am very well conscious that I have no idea where to start.

teemingc · 2025-11-23T07:10:02Z

Hey @teemingc is there any way we can help in moving this PR forward? I could try and spend some time on it, but I am very well conscious that I have no idea where to start.

Hey @Giggiux we’re waiting until SvelteKit 3 before we move to the environment API

- Upgrade to Vite 7.0.3 and add pnpm override to ensure consistent versions - Add sveltekit_vite_environment virtual module for dev-time manifest access - Add DevEnvironment type for sharing state between plugin and dev server - Add environment.js utilities for module resolution in Vite environments - Update dev server to populate and invalidate environment module - Support environments config for future isolated builds This is a minimal port of the Environment API changes from PR sveltejs#14008, enabling Vite 7 support while maintaining compatibility with existing adapters.

teemingc · 2026-02-05T11:00:40Z

Closing this because we'll be starting this from scratch next week

kvanbere · 2026-02-21T01:34:36Z

Is there a new PR for it?

benmccann · 2026-02-24T23:40:41Z

package.json

-		]
+		],
+		"overrides": {
+			"esm-env": "github:benmccann/esm-env#bcbddbc&path:packages/esm-env"


just curious, is there a reason you had to do this? is there anything you need me to fix in it?

Related to benmccann/esm-env#20

petebacondarwin · 2026-04-05T15:26:41Z

Is there a new PR for it?

This I think: #15627

Chew Tee Ming added 2 commits July 17, 2025 13:03

wip

f77bc70

Merge branch 'main' into environment-api

71e3d5a

teemingc added vite pkg:adapter-cloudflare labels Jul 17, 2025

teemingc marked this pull request as draft July 17, 2025 05:26

add files to files array

498ef93

benmccann added the breaking change label Jul 17, 2025

benmccann added this to the 3.0 milestone Jul 17, 2025

bump peer dep

b3d902f

Chew Tee Ming added 3 commits July 18, 2025 10:45

Merge branch 'main' into environment-api

eaaa487

use node 20 types

d5b7786

ignore virtual modules when optimising deps

ef4d10e

teemingc mentioned this pull request Jul 22, 2025

feat: support custom worker output path for easier integration of cloudflare worker handlers #14029

Closed

6 tasks

Chew Tee Ming added 12 commits July 24, 2025 13:52

try this to avoid prebundling kit in worker

a02fbfa

Merge branch 'main' into environment-api

5d0ede5

export server from different path

4ca01c9

optimise cjs deps

21ee281

with dep optimisation

9158a25

without dep optimisation

f4eb279

patch until cloudflare vite plugin releases

99d8a2f

correctly handle static assets in dev

7f1feb1

Merge branch 'main' into environment-api

911717f

always optimize deps

2ee2c2c

remove workaround

463cd5d

fix svelte context not being set correctly

7fdfe68

im changing latops so just commit wip

ad109ad

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This was referenced Nov 25, 2025

feat: allow additional handlers to be exported by adapter-cloudflare #13739

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feature request: vite plugin with sveltekit cloudflare/workers-sdk#8922

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teemingc closed this Feb 5, 2026

benmccann reviewed Feb 24, 2026

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