Feature request: support exporting Rust constants to TypeScript

[Choochmeque]

Is your feature request related to a problem? Please describe.
Currently, ts-rs can export structs and enums, but not constants.
This leads to duplicated definitions between Rust and TypeScript for shared values (like filenames, setting keys, limits, etc.), which can easily get out of sync.

Describe the solution you'd like
Allow ts-rs to export pub const values to TypeScript.
Example:

pub const SETTINGS_FILE: &str = "settings.json";

to

export const SETTINGS_FILE = "settings.json";

This could also work for numeric and boolean constants:

pub const MAX_ITEMS: u32 = 100;
pub const DEBUG_MODE: bool = true;

to

export const MAX_ITEMS = 100;
export const DEBUG_MODE = true;

Describe alternatives you've considered

• Manually duplicating constants in Rust and TypeScript.
• Custom build scripts to generate TS files separately.

Additional context
This would improve type safety and maintainability for shared front/back-end projects (e.g., Tauri apps).

[timephy]

I'd like that too.

Sadly having something like this is currently not possible:

#[export_const(X)]
const X: i32 = 3;

Because you cannot have macros on const definitions.

However an approach similar to lazy_static could work I believe:

export_const! {
    const X: i32 = 3;
}

---

For Discussion:

Currently the purpose of this lib is "Generate typescript type declarations from rust types".
So I guess a question to the maintainers is: Is implementing something like this "wanted"? Would you be open to it?

[NyxCode]

I'd be open to such a feature!
I'm not yet entirely sure how to do this in a robust and general manner, and in such a way that it plays nicely with the dependency tracking infrastructure. But I'd love some suggestions!

[timephy]

I believe we can simply use serde_json, the result should be valid TypeScript.
Then slap on the type and it should be good to go.

[timephy]

Just wanted to leave one more thought:
It might be nice to export a simple Enum as an array of its variants. So one can iterate over its variants in TypeScript.