[apitman]

Seeing Bun/Node/Deno support reminds me of a question: are there any good resources on writing JS that works in all 3 and the browser? For example if I wanted to write a simple filesystem API that would work the same across bunodeno?

[TheFuzzball]

I think you'd have to write a facade package with a consistent API that mapped to the node/deno/bun equivalents, since they're each quite different.

Best bet is to use the Node fs package and rely on the deno/bun compatibility layer.

More generally, Deno pushes for Web Platform APIs, and as more are proposed and implemented the runtime-specific APIs will become fewer and fewer.

[apitman]

Yeah this is basically what I'm trying to do (see response to sibling). Unfortunately I consider Node's APIs the worst of the 3. No shade on them it's just an older design. I really like Deno's approach since my code also needs to work in the browser. Writing HTTP handlers that take Request[0] and return Response[1] is a beautiful bit of symmetry with frontend code and feels like cheating.

[0]: https://developer.mozilla.org/en-US/docs/Web/API/Request

[1]: https://developer.mozilla.org/en-US/docs/Web/API/Response

[ascorbic]

If you use Node 20+ then there's a lot more compatibility with web platform APIs, so it is possible to write code that works on Node, browser and WinterCG-compatible runtimes like Deno. Obviously you'll need to avoid using Node builtins.

[lakpan]

Bun’s goal is to be an actual superset of node, so you can write just for node and expect it to work in bun.

As for deno, I think if you publish ESM you’re mostly covered since deno can install from the npm registry.

[selfmodruntime]

You can't, and for good reason. Deno has slightly different API's than Node. Bun also has subtle differences between their STL implementation and Node's, but afaik, they're getting there.

[apitman]

I think maybe I was unclear. I'm talking about writing libraries that abstract across these differences and provide a single API, as sibling describes. I already know it's possible. I made a simple filesystem abstraction here[0] and a very simple HTTP library that uses it here[1]. They both work in Node/Deno and the browser. Unfortunately I ran into issues with Bun's slice implementation[2], but that should be fixed eventually.

My overall question is that I suspect there's a much better way of detecting and using the different backends, and I'm wondering what techniques are out there.

[0]: https://github.com/waygate-io/fs-js

[1]: https://github.com/waygate-io/http-js

[2]: https://github.com/oven-sh/bun/issues/7057