Incorrect TS types generated from types containing type aliases

[FruitieX]

Minimal repro:

use std::collections::HashMap;
use ts_rs::TS;

type TypeAlias = HashMap<String, String>;

#[derive(TS)]
#[ts(export)]
enum Enum {
    A(TypeAlias),
    B(HashMap<String, String>),
}

#[derive(TS)]
#[ts(export)]
struct Struct {
    a: TypeAlias,
    b: HashMap<String, String>
}

fn main() {}

Generates:

export type Enum = { A: Record } | { B: Record<string, string> };

export interface Struct { a: Record, b: Record<string, string>, }

Expected both generated variants/fields to be identical.

[NyxCode]

The current processing of types with generic parameters breaks with type aliases since the generic parameters are not explicitly named in-place where the type is used.

[FruitieX]

A workaround for now is to just avoid type aliases in anything generic* that needs to be exported. Use newtype structs instead:

pub type MyType = HashMap<string, string>;

becomes

#[derive(TS)]
#[ts(export)]
pub struct MyType(pub HashMap<string, string>);

In addition you can now export TS bindings to these types as well. Of course you will have to adapt your code somewhat to support (un)wrapping these newtype structs.

[NyxCode]

type aliases do work as long as the type they alias is not generic

[oscartbeaumont]

I have run across this same issue. Luckily I can workaround the issue by using wrapper types like what has been documented above.

I gave fixing the issue a shot and very quickly noticed I was way out of my depth, I have however created some tests which show the specific issue I had on my fork here. I thought I would post them in case they can help anyone.