Reagovať ako aktualizovať stav pole
Príklady kódu
ako pridať údaje poľa o stave reagovať
this.setState({ myArray: [...this.state.myArray, 'new value'] }) //simple value
this.setState({ myArray: [...this.state.myArray, ...[1,2,3] ] }) //another array
ako aktualizovať pole v stave reakcie
this.setState(prevState => ({
arrayvar: [...prevState.arrayvar, newelement]
}))reagovať ako aktualizovať stav pole
const initialState = [
{ name: "foo", counter: 0 },
{ name: "far", counter: 0 },
{ name: "faz", counter: 0 }
];
const [state, setState] = useState(initialState);
const clickButton = () => {
// 1. Make a shallow copy of the array
let temp_state = [...state];
// 2. Make a shallow copy of the element you want to mutate
let temp_element = { ...temp_state[0] };
// 3. Update the property you're interested in
temp_element.counter = temp_element.counter+1;
// 4. Put it back into our array. N.B. we *are* mutating the array here, but that's why we made a copy first
temp_state[0] = temp_element;
// 5. Set the state to our new copy
setState( temp_state );
}Podobné stránky
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