- [#4](https://github.com/lukemorales/exhaustive/pull/4) [`b287bbb`](https://github.com/lukemorales/exhaustive/commit/b287bbbb0fcb7a5f433bff2ff4124d5ae995a8ed) Thanks [@lukemorales](https://github.com/lukemorales)! - ## Exposed `Exhaustive` types and added new generic slot in core function for type of output

The types `ExhaustiveUnion` and `Exhaustiveag` are now exposed for your own convenience if you'd like to override the generic slots of `exhaustive`. The inferred output was also added as a new slot in the function generics, allowing you to also override the output value of `exhaustive`:

```tsx

import { exhaustive, type ExhaustiveTag } from "exhaustive";

exhaustive<

RequestState,

"state",

ExhaustiveTag<RequestState, "state">,

JSX.Element

>(request, "state", {

IDLE: () => null,

LOADING: (value) => <Loading />,

SUCCESS: (value) => <List data={value.data} />,

ERROR: (value) => <Error message={value.error} />,

});

```

### BREAKING CHANGES

#### Renamed `_tag` method to `tag`

The `_tag` method was exposed as a some sort of secondary method to enhance the experience with Tagged Unions. Since the DX of using it is vastly superior compared to the Tagged Union overload in `exhaustive`, and it seems that we cannot improve the overload inference on the core funcion, the underscore has been removed from the method name and now you should used it as `exhaustive.tag` to make it official as the preferred way to exhaustive check Tagged Unions:

```diff

const area = (s: Shape) => {

- return exhaustive._tag(s, 'kind', {

+ return exhaustive.tag(s, 'kind', {

square: (shape) => shape.size ** 2,

rectangle: (shape) => shape.width * shape.height,

circle: (shape) => Math.PI * shape.radius ** 2,

});

};

```

- [#4](https://github.com/lukemorales/exhaustive/pull/4) [`b287bbb`](https://github.com/lukemorales/exhaustive/commit/b287bbbb0fcb7a5f433bff2ff4124d5ae995a8ed) Thanks [@lukemorales](https://github.com/lukemorales)! - ## Add `exhaustive.tag` overload to core function

The same functionality of `exhaustive.tag` is available in the main function by adding a third argument to `exhaustive` that will trigger the Tagged Union overload.

```ts

const area = (s: Shape) => {

return exhaustive(s, "kind", {

square: (shape) => shape.size ** 2,

rectangle: (shape) => shape.width * shape.height,

circle: (shape) => Math.PI * shape.radius ** 2,

});

};

```

PS: Note that TypeScript has a limitation inferring the Tagged Union overload via argument types because they are generic values. Typescript will only fallback to the Tagged Union overload when you add a third argument. This means autocomplete for the Tagged Union keys will not exist until you declare an empty object as the third argument:

```ts

exhaustive(shape, "kind", {});

// ^ this will trigger the Tagged Union overload

```

This feature is being added as a reflect of how the API was originally intended. Use it at your own convenience, but if you prefer the better DX of inferred types from the start, calling `exhaustive.tag` is still preferrable.

"version": "1.0.0",