🚀 Feature Request: support import with type syntax (standard now)

[treeder]

Describe the solution

Workers can import JSON like this:

import Something from './file.json'

But you can't do that anywhere else.

This works in Chrome, Node, etc:

import Something from './file.json'  with {type: "json"}

But does not work in workers, you get:

It would be nice to have workers support "with type" so it can be used in various places without having to change it specifically for workers.

Spec: https://github.com/tc39/proposal-import-attributes

Supported almost everywhere: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import#browser_compatibility

[valtlai]

I just needed this to use the Fedify ActivityPub server framework on Workers. This one cannot be polyfilled as it’s a syntax feature, so I had to strip the import attributes with a post-install script.

[treeder]

@edmundhung thoughts on this? Should be backwards compatible and would unbreak using packages that use this. You could even just strip it/ignore it and it would work the same in wrangler/workers.

[treeder]

I should add why this is important, because node REQUIRES this, it doesn't work without it.

[irvinebroque]

@treeder try Wrangler v4 prerelease which has an updated version of esbuild:

#7334

Would love feedback! cc @penalosa

[penalosa]

@treeder you should be able to try it out by using npm install wrangler@next

[treeder]

Nice, will try today.

[valtlai]

I can confirm import attributes work on wrangler 4. However, I think it’s better to install wrangler@v4-rc, which should be more stable.

[treeder]

If we use this v4, will it work when deployed?

[emily-shen]

If we use this v4, will it work when deployed?

Yes it will! The worker that is uploaded at deployment should be JS anyway. you can always add the --dry-run flag as well to test deployments without actually deploying

[treeder]

This is JS. Does the runtime support modern JS like this or does it strip these modern things out or something?

[irvinebroque]

@treeder when you use wrangler, wrangler is bundling your code first with esbuild internally. So that bundler needs to understand import attributes — that's what Wrangler v4 piece is doing here.

Natively in the runtime itself — working on that (see: cloudflare/workerd#1553) so that how we handle module resolution more closely matches standards, so that we can support import attributes, etc.

But in the base case your code is bundled up first before it's given to the Workers runtime.