Using createAsyncThunk and the builder API to Generate Redux Actions for an API call

The key reason to use createAsyncThunk is that it generates actions for each of the different outcomes for any promised-based async call: pending, fulfilled, and rejected. We then have to use the builder callback API on the extraReducers property to map these actions back into reducer methods we then use to update our state. It's a bit of of a process but it's simpler than the alternative, which is to create a bunch of actions by hand and manually dispatch them.

• createAsyncThunk takes a type argument (which I referred to as a label) and a function called a payloadCreator which is basically just an async function (or function returning a promise) that goes and collects data.

• The builder API is one way to define extraReducers (you can also pass in an object with a string). It's semantically similar to a switch statement and includes methods like addCase and addDefaultCase.