Show HN: Crust – A CLI framework for TypeScript and Bun
Comments
camkego
embedding-shape
Both in the frontend and the backend, I've usually used "If it calls your code, it's a framework, if you call its code, it's a library", and would seem to fit here too. An argument parser you'd call from your main method, then do stuff with what it returns. In Crust, it seems you instead setup the command + what will happen when it's called, then let the framework call your code.
codybontecou
That’s… actually a great definition. I’m going to try to retain that.
jazzypants
This is classically called "Inversion of Control"[0] or the "Hollywood Principle"[1] as in "Don't call us-- we'll call you".
[0] - https://martinfowler.com/bliki/InversionOfControl.html [1] - https://wiki.c2.com/?HollywoodPrinciple
jellyotsiro
good point.
we’re using “framework” intentionally because it goes beyond argument parsing. crust handles parsing, but also:
type inference across args + flags end to end compile-time validation (so mistakes fail before runtime) plugin system with lifecycle hooks (help, version, autocomplete, etc.) composable modules (prompts, styling, validation, build tooling) auto-generates agent skills and modules from the CLI definitions
so it sits a layer above a traditional arg parser like yargs or commander, closer to something like oclif, but much lighter and bun-native.
chenxin-yan
Hi, I called it "CLI framework" because it is more of a ecosystem of modules that contains everything you need to build a CLI, argument parsing is just part of it. The @crustjs/core module is the argument parser, and there are more modules such as @crustjs/skills that would derive agent skills from your command definition, @crustjs/store that state persistent and so on
lozf
also: no "C", and no "rust", despite being a portmanteau of both these other languages names :)
hdjrudni
I was looking for something like this.
Does the help plugin not support color?
Looks like the spacing is messed up too. I just converted my app to use it and its coming out like
``` COMMANDS: export-schemaExport table definitions from existing database to YAML export-dataExport table data in CSV format import-dataImport table data from CSV file schema-sqlConvert YAML schema back to MySQL export-usersExport users in YAML format users-sql Convert users.yaml back into SQL export-allExport all data from host export-all-tgzExport all data from host databases-sqlConvert databases.yaml back into SQL export-typescriptExport TypeScript interfaces ```
i.e. there's no space after `export-schema` it just goes immediately to the description.
chenxin-yan
I will add color support for help plugin later. open a issue if you found bugs or improvement
derodero24
The plugin system and compile-time validation are nice touches. My main concern would be the standalone binary size — 58-109MB is a lot for a CLI tool. Most Go CLIs land around 10-20MB and even that gets complaints. Is there a way to strip unused features, or is this mostly the Bun runtime being bundled?
babarot
The binary size is my main hesitation with Bun-based CLIs too. For comparison, a typical Go CLI with cobra compiles to ~10MB statically linked, and you get cross-compilation for free. The plugin system and compile-time validation here are genuinely nice though — Go's CLI ecosystem doesn't have anything equivalent to that.
derodero24
Yeah exactly. Go's ~10MB binaries with dead-simple cross-compilation is tough to compete with. I think Bun makes more sense for internal tools where you control the install and care more about the plugin ecosystem than distribution size.
GutenYe
Looks cool. If anyone is interested in a simple option with autocomplete working out of the box and no extra bells and whistles, feel free to check out my project: https://github.com/gutenye/script.js
bennettpompi1
this is cool! i'd recommend fleshing out the README. Clicked on the link before the discussion and was a tad confused.
chenxin-yan
Hi, I will update the README.md to make it more informative. The reason I left it kinda empty is because curst has a website that have more details about this project at crustjs.com. I just had the link in README.md for now
jellyotsiro
will fix in the next hour!
nullstyle
I’ve been using the jsr:@cliffy/* packages from deno to solve the same problem.
bpev
yup yup same. That one's worked well for me. Between that and the deno std, it's nice to have it feel like mostly everything you need is available with very little searching.
landl0rd
Is there an examples section? Would be helpful to see a demo
jellyotsiro
one of the examples would be trynia.ai (search and index api for ai agents)
here is github: github.com/nozomio-labs/nia-cli
qyron
Any plans to support Node.js? Also some comparison (at least design choices) with existing frameworks would be nice.
chenxin-yan
Technically most modules would work with node.js as they are not using any bun specific APIs. The reason for crust to be all in bun is because bun can compile your cli into binaries for distribution which powers curst build. The idea is that since you will have bun bundled with your CLI to end user. the developer does have to worry about the end users don't have bun installed and use Bun api freely when building.
iktakahiro
As a Bun user, this caught my eye. Gonna give it a try!
rgbrgb
nice, congrats on launch. To get an idea... what's the size of a standalone hello world cli binary?
jellyotsiro
tens of KBs (v small)
rgbrgb
Isn't a standalone Bun binary like 50MB because it has to bundle the runtime? How could this get smaller?
chenxin-yan
Hi, the creator of crust here, the binary size varies between platforms. With the hello world cli, the smallest, on darwin-arm64 it is 58.1M, the largest on windows-x64 is 109M. hope this helps!
matt_kantor
> Versions before 1.0 do not strictly follow semantic versioning.
Sorry for being nitpicky, but yes they do. Semantic versioning[0] allows arbitrary changes while the major version is 0:
> Major version zero (0.y.z) is for initial development. Anything MAY change at any time. The public API SHOULD NOT be considered stable.
[0]: https://semver.org/
chenxin-yan
Hi, the comment I left in README.md is just to warn user that do expect breaking changes before 1.0 for THIS PROJECT specifically. there is no implication that semver as a standard is promoting arbitrary changes/version before 1.0.
matt_kantor
I get that, and it's a nice thing to warn users about. My nitpick was merely about the specific "do not strictly follow semantic versioning" phrasing. There's nothing you can do in a 0.y.z release which doesn't follow the SemVer spec (e.g. your next release could turn the project into a spell checker instead of a CLI framework and you'd still be in compliance).
chenxin-yan
ohh thank you for pointing that out. I just double checked the semver docs and it makes sense now. Something new I learned today
jellyotsiro
thanks for the catch, what we meant is that we’re not committing to strict stability guarantees yet, so APIs may still change as we iterate toward 1.0.
matt_kantor
I understand, but that's already implied by a 0.y.z version number.
olivia-banks
I will say that this doesn't seem to be how semver is used in the wild, which I would argue is more important. I personally didn't know about this rule. Tons of Rust projects follow semver don't follow it either, and just stay on 0.x.y forever.
matt_kantor
How is it used in the wild, in your experience? Have you observed projects following some alternate set of rules?
I thought projects that stay on 0.x.y forever mostly do it because it means they're allowed to break things. Also, since 0.x.y means "anything goes", projects can introduce their own conventions within that range without violating the spec.
I know that some package managers (including Cargo and npm) confusingly treat 0.1.0 → 0.1.1 like a "minor" update, despite the spec. Is this what you're referring to?
olivia-banks
Yes, that was what I was referring to, although I thought the reason of staying at 0.y.z was more of a cultural one. v0, at least to me, implies that the API may change arbitrarily and quickly, but makes no assertions about the actual versioning scheme itself.
There's a website making fun of it: https://0ver.org/
todteera
seems pretty useful and easy to setup
optivly
wow, cannot wait to start with this
leontloveless
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rrojas-nexus
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kaihong_deng
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dnlzro
Psst, the GitHub link in your post is broken (it should be https://github.com/chenxin-yan/crust).
dang
Fixed above. Thanks for the heads-up!
jellyotsiro
thanks for flagging! the post itself works, just the link at the bottom
This looks useful. But, it's interesting how the backend-world and front-end world keep diverging. I must admit, I had no idea what this was from the title. "CLI framework"? But in backend-land, these would typically be called "argument parsers" or "command line argument parsers". But maybe I am missing some of the functionality.