Discussion on: Redux Toolkit Basic Intro

Nice post, and glad to hear that RTK is working well for you!

A few quick notes on the code samples:

First, you may actually have a small issue with one of those reducers:

reducer: ( state, { payload }) => state.push(payload),

Immer wants you to either return a new value, or mutate its state, but not both. This is mutating with push(), which is fine, but also returning the result of push() because of the implicit arrow return. Immer will probably yell at you for that. You can fix it by throwing curlies around the body, or putting void in front of the body.

The findIndex() calls look like they're missing a = assignment. Personally, I'd call find() instead of findIndex():

const todo = state.find(todo => todo.id === payload.id)
if(todo) {
  todo.completed = !todo.completed;
}

Finally, while it's totally fine to use a findIndex() + a splice() to remove an item, I find it's usually shorter to do it with a .filter() instead and just return the new array same as you would with more traditional hand-written reducers. (And that's one of the nice things about Immer and RTK - you can mix and match update styles as appropriate!)

Also, the link to the "Why RTK uses thunks" post is going through an odd Youtube redirect first. The actual link is blog.isquaredsoftware.com/2020/02/... - would be good to update to point to that directly.