@joakin/sum-types

``
npm install sum-types
`

sum-types provides union|adt|sum types for JS.

Exhaustiveness checking, Maybe and Result types, and a nice API.

Read the docs

`js
import { Type } from "@joakin/sum-types";

const State = Type({
Loading: [],
Success: ["data"],
Error: ["error"]
});

let state = State.Loading();
let state = State.Success(42);
let state = State.Error(new Error("Failed"));

function toString(state) {
return state.match({
Loading: _ => "Loading",
Success: data => Got data ${state.data},
Error: err => Got error: ${state.error}
});
}

// Or

const toString = State.match({
Loading: _ => "Loading",
Success: data => Got data ${state.data},
Error: err => Got error: ${state.error}
});
``