The `mapDispatchToProps()` function is used to provide specific action creators to your React components so they can dispatch actions against the Redux store. It's similar in structure to the `mapStateToProps()` function you wrote in the last challenge. It returns an object that maps dispatch actions to property names, which become component `props`. However, instead of returning a piece of `state`, each property returns a function that calls `dispatch` with an action creator and any relevant action data. You have access to this `dispatch` because it's passed in to `mapDispatchToProps()` as a parameter when you define the function, just like you passed `state` to `mapStateToProps()`. Behind the scenes, React Redux is using Redux's `store.dispatch()` to conduct these dispatches with `mapDispatchToProps()`. This is similar to how it uses `store.subscribe()` for components that are mapped to `state`.
For example, you have a `loginUser()` action creator that takes a `username` as an action payload. The object returned from `mapDispatchToProps()` for this action creator would look something like:
The code editor provides an action creator called `addMessage()`. Write the function `mapDispatchToProps()` that takes `dispatch` as an argument, then returns an object. The object should have a property `submitNewMessage` set to the dispatch function, which takes a parameter for the new message to add when it dispatches `addMessage()`.