Introduction

const reducer = (state, action) => {
   switch (action.type) {
      case "SOME_ACTION":
           // update state
           return {
              age: state.age + 1
           }
      break;



      default:
          return state

   }
}




const [state, dispatch] = useReducer(reducer, {age: 32})



function handleClick() {
    dispatch({type: "SOME_ACTION"})
}