react hooks useState assignment optimization solutions

// performance optimization point, very little into multiple, web pages will become the favored manufacturers

// as a function hooks

React Import, useState {} from 'REACT'; 
// Import from ToDoList './TodoList'; 
function the App () { 
the let A =. 1; 
   the console.log (. 1) // update data can be seen, once executed, let a be performed above, when more data loss performance. 
  const [b, setb] = useState (a); // hooks destructuring assignment 
  return ( 
    <className = div "the App"> 
      {B} 
      <= {Button the onClick () => {SETB (B +. 1)}}> < / Button> 
    </ div> 
  ); 
} 

Export default the App;

　　// can be used in the following manner

React Import, useState {} from 'REACT'; 
// Import from ToDoList './TodoList'; 
function the App () { 
  // the console.log (. 1) 
  const [B, SETB] = useState (() => { 
    the let =. 1 A; 
    the console.log (A); // you can see this way, only the first data initialized when high data efficiency performance. 
    return A; 
  }); 
  return ( 
    <className = div " the App "> 
      {B} 
      <= {Button the onClick () => {SETB (B +. 1)}}> </ Button> 
    </ div> 
  ); 
} 

Export default the App;