@Kevin W does itty-durable "just work" when it comes to types? - Cloudflare Developers

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johtso

Jjohtso Another question, what's the go to way to get a type safe interface between my D...

DanTheGoodman

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DanTheGoodman•3/9/23, 3:23 PM

they are bound together, and can share types in the codebase

DanTheGoodman

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DanTheGoodman•3/9/23, 3:23 PM

Do you mean runtime-safe? It's better to validate inputs and assume they are as expected once they enter the system rather than checking everywhere

DanTheGoodman

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DanTheGoodman•3/9/23, 3:24 PM

If you need runtime type checking you can use something like zod

DanTheGoodman

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DanTheGoodman•3/9/23, 3:24 PM

Hono has better typing across the board, I've used both itty-router and hono. I prefer to stay away from itty-durable but that would have better typing. I stay away because I don't like how differnet it is from making normal DOs

johtso

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johtsoOP•3/9/23, 3:25 PM

@danthegoodman this looks promising https://www.npmjs.com/package/trpc-durable-objects

npm

trpc-durable-objects

Testing out trpc for durable objects. Latest version: 1.0.4, last published: 19 days ago. Start using trpc-durable-objects in your project by running npm i trpc-durable-objectsnpm i trpc-durable-objects. There are no other projects in the npm registry using trpc-durable-objects.

johtso

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johtsoOP•3/9/23, 3:25 PM

Just looking to reduce boilerplate

DanTheGoodman

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DanTheGoodman•3/9/23, 3:25 PM

Are you just trying to get strong type checking?

DanTheGoodman

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DanTheGoodman•3/9/23, 3:26 PM

just type check when requests come it, then you can assume they are safe once they are in the system

DanTheGoodman

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DanTheGoodman•3/9/23, 3:26 PM

so at the worker type check everything before passing to a DO

DanTheGoodman

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DanTheGoodman•3/9/23, 3:26 PM

many many packages for that

johtso

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johtsoOP•3/9/23, 3:26 PM

I want to be able to call a method of my DO from my worker as if it was a local function, and have the correct types, and have the response validated

DanTheGoodman

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DanTheGoodman•3/9/23, 3:28 PM

Ultimately you will be at the mercy of that package, it's not really worth it in my experience of making many production systems on workers and DOs. Keep with the request/response semantics because that is what's actually happening, and that decouples you from dumb decisions or lack of updates from third party packages

DanTheGoodman

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DanTheGoodman•3/9/23, 3:28 PM

but that's very much an opinion... personally I'd never use a small package like that in production, I'm not about to maintain someone else's code when I need changes if that makes sense

DanTheGoodman

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DanTheGoodman•3/9/23, 3:29 PM

going from 5 lines per function to 2 is not worth all that hoop jumping IMO

DanTheGoodman

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DanTheGoodman•3/9/23, 3:29 PM

premature optimization is the common terminology here

johtso

Jjohtso @Kevin W does itty-durable "just work" when it comes to types?

Kevin

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Kevin•3/9/23, 3:31 PM

Currently itty-durable itself (the invisible code) is not typed at all, but you can easily type your objects as you define them, then use those types throughout your worker code.

Kevin

KKevin Currently itty-durable itself (the invisible code) is not typed at all, but you ...

johtso

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johtsoOP•3/9/23, 3:39 PM

For example will the return value of COUNTER.get('myCounter').currentValue()COUNTER.get('myCounter').currentValue() be typed as a number if the DO method returns a number?

johtso

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johtsoOP•3/9/23, 3:49 PM

Looks like there's no typescript stuff going on, so you'd have to do something like as ReturnType<typeof Counter.currentValue>as ReturnType<typeof Counter.currentValue>

Kevin

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Kevin•3/9/23, 4:07 PM

I would do something like const MyObj = DO.get(‘foo’) as MyDurableClass

johtso

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johtsoOP•3/9/23, 4:08 PM

Oh wow, that's a great idea

Kevin

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Kevin•3/9/23, 4:08 PM

to just get the full typings at once

Kevin

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Kevin•3/9/23, 4:10 PM

I’ve had to use that pattern at various places throughout worker code, esp as you pile on more magic… it just reconnects the types that may have been lost or difficult to drill through your app

johtso

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johtsoOP•3/9/23, 4:11 PM

I could probably even do some PickPick magic so it only exposes router methods

johtso

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johtsoOP•3/9/23, 4:14 PM

Although looking at the code it exposes anything that isValidMethodisValidMethod except for fetch

Kevin

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Kevin•3/9/23, 4:15 PM

Yeah, I don’t think it would grab the internal itty-durable methods

johtso

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johtsoOP•3/9/23, 4:16 PM

constructor method?

Kevin

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Kevin•3/9/23, 4:17 PM

I assume the types would refer to your own constructor, if you have one

Kevin

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Kevin•3/9/23, 4:18 PM

I’m in the middle of a massive overhaul of itty-router, bringing CORS and extras into the main lib, so itty-durable is next for a full TS conversion at least where it matters)

johtso

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johtsoOP•3/9/23, 4:19 PM

Awesome!

johtso

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johtsoOP•3/9/23, 4:21 PM

I do wonder how the trpc approach differs. I do like that you're basically just writing functions that get passed the DO as ctx

johtso

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johtsoOP•3/9/23, 4:21 PM

And that the requests actually get validated using zod

Kevin

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Kevin•3/9/23, 4:22 PM

Have a link for that?

Kevin

KKevin Have a link for that?

johtso

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johtsoOP•3/9/23, 4:23 PM

https://github.com/markusahlstrand/trpc-durable-objects

GitHub

GitHub - markusahlstrand/trpc-durable-objects: A POC for using trpc...

A POC for using trpc for cloudflares durable objects - GitHub - markusahlstrand/trpc-durable-objects: A POC for using trpc for cloudflares durable objects

Kevin

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Kevin•3/9/23, 4:23 PM

Personally I don’t love tRPC much myself, but that’s just cuz it feels boilerplatey to me… I’m sure it’s great for folks that like it!

johtso

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johtsoOP•3/9/23, 4:23 PM

Interesting how it's flipped on its head.. with this approach it creates a DO class for you based on your router

johtso

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johtsoOP•3/9/23, 4:24 PM

Where as itty-durable you define the class but subclass something

johtso

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johtsoOP•3/9/23, 4:25 PM

The example looks rather succinct

Kevin

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Kevin•3/9/23, 4:25 PM

Haha yeah… see, that’s the part that I didn’t want to have to think about when making DOs. I only want to care about the business logic… in the case of a counter for instance, just the value and the increment. All the rest of the native DO code was noise IMO… the storage bits, fetch, internal routing, even building a request from the Worker.

Kevin

KKevin Haha yeah… see, that’s the part that I didn’t want to have to think about when m...

johtso

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johtsoOP•3/9/23, 4:29 PM

Looks like this takes a similar approach, you just define a tRPC router with your business logic

johtso

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johtsoOP•3/9/23, 4:30 PM

Obviously doesn't have the persistence magic though

johtso

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johtsoOP•3/9/23, 4:32 PM

Obviously the definition isn't as minimal because you write the method input shape using a zod scheme instead of just method arguments, but that gets you type safety

johtso

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johtsoOP•3/9/23, 4:33 PM

I guess it also doesn't have the idea of querying arbitrary properties

Kevin

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Kevin•3/9/23, 4:33 PM

I think just writing your DO a in full TS and casting the stub as you grab it in the Worker should still get you that… I’ll do some tests to confirm this

Kevin

KKevin I think just writing your DO a in full TS and casting the stub as you grab it in...

johtso

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johtsoOP•3/9/23, 4:34 PM

I guess the only problem with this is you're still not validating, just asserting

Kevin

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Kevin•3/9/23, 4:34 PM

I sometimes forget about that feature… I basically always use the methods to interact w the DO now, not awaiting direct props

johtso

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johtsoOP•3/9/23, 4:34 PM

Although I'm not sure when that might cause problems..

johtso

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johtsoOP•3/9/23, 4:35 PM

A deployment screwup where your worker doesn't get updated?

johtso

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johtsoOP•3/9/23, 4:38 PM

Oh wait.. trpc doesn't even actually do runtime validation?

Kevin

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Kevin•3/9/23, 4:41 PM

If you think of a DO as a stateful object, I don’t think validation there makes much sense personally… as the real point of contact between an external source and any form of input is really at the Worker level. I’d put validation there.