1 let memoizedState;    
 2 function useReducer(reducer, initialArg, init) {    
 3   let initState = void 0;    
 4   if (typeof init !== 'undefined') {    
 5     initState = init(initialArg)    
 6   } else {    
 7     initState = initialArg    
 8   }    
 9   function dispatch(action) {    
10     memoizedState = reducer(memoizedState, action)    
11     render()    
12   }    
13   memoizedState = memoizedState || initState    
14   return [memoizedState, dispatch]    
15 }    
16     
17 function useState(initState) {    
18   return useReducer((oldState, newState) => newState, initState)    
19 }