Learn React Hooks

Reducers

We defined three reducers—one for each part of our state—and an app reducer to combine the other two reducers. The filter reducer waits for a FILTER_TODOS action, and then sets the new filter accordingly. The todos reducer listens to the other todo-related actions, and adjusts the todos array by adding, removing, or modifying elements. The app reducer then combines both reducers, and passes actions down to them. After defining all the elements that are needed to create a Redux application, we can now set up the Redux store.