Async Actions

What makes middleware so powerful is the access to both getState() and dispatch(), as these functions allow a middleware to run asynchronous actions and give it full access to the store. A very simple example would be an action debounceused to save state only after a period of inactivity middleware. Suppose we have an autocomplete field, and we want to prevent the AUTO_COMPLETE action from running as the user types in a search term. We would probably want to wait 500 ms for the user to type in part of the search string and then run the query with the latest value.

We can create a debounce middleware that will catch any action with the debounce key set in its metadata and ensure it is delayed by the ...