Redux Guards

Redux Guards are a pattern of leveraging TypeScript's type guards for a concise, fully-typed Redux application.

See the introductory blog post for a detailed look at this solution.

Try It Out

Clone this repo, and navigate to the examples directory:

$ cd examples/kitchen-sink
$ yarn install
$ yarn start

I recommend checking out the example project in VSCode to inspect the typings and code hints.

Approach

With Redux Guards, you will define three pieces to enable type safety across your dispatch() boundary:

• An action-creator-creator function, which encodes runtime type information
• A type guard that accepts action-creator functions created above
• A dispatch() module augmentation to account for middleware and adjustments made to our action creators

If you have questions or would like to see a middleware example added to the project, feel free to open an issue and I will try to help out.

Pull Requests are appreciated!

Consider Copy-Pasting!

Redux Guards is meant to be a pattern rather than a library.

While this is an NPM package, I highly recommend copying the code from /src instead. Most of your middleware-specific type guards will be tightly coupled to your state. Since TypeScript does not support skipping some generics, it can become very un-ergonomic to attempt to allow AppState to be an optional generic. Until that issue is closed, having a state-generic approach will not be possible.

Also, nearly all Redux applications have only a single store and AppState. Having these coupled to your type guards makes things much simpler when consuming within the reducer, and is just easier to understand in general.

Redux Pack Type Forking

I found it necessary to fork and re-type the official Redux Pack types. I haven't had time to validate and PR upstream. The official types don't properly define the Handler-Reducer.

Forked from typescript-lib-starter