The counter demo of react plus redux and the counter.jsx of reduers inside have no counter attribute. Why can they be counted?

  node.js, question

This and that official demo
The counter.jsx of reducers inside is shown in the figure. The state inside here obviously does not have a counter, but the counter.jsx of actions inside can get the attribute of counter through getState (). I can’t change {counter} into {any caption}
In addition, Confederates inside’s App.jsx has also been used, and state can point out the counter
Is there a great god who can explain in detail why the state has the attribute counter? Is getstate () a built-in method for actions and can you get the State of reducer inside?
Thank you

The data structure in redux is consistent with the combined structure of reducers, and the key of data corresponds to the key of reducer combine. if there is only one reducer, when creating store, for exampleconst store = createStore(counter); store.getState(); //The obtained data organization is {counter: xxx}.getState()Redux is the api of redux. Users get Redux’s state, which is all the data. The data obtained in the example is{counter: xxx}