/Javascript/React/How to update react state array

How to update react state array

React how to update state array

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 );
}

Source: stackoverflow.com

React native update state array of objects

let markers = [ ...this.state.markers ];
markers[index] = {...markers[index], key: value};
this.setState({ markers });

Source: stackoverflow.com

How to update react state array

const [array, setArray] = useState([1, 2, 3])

// Add
setArray(prevArray => [...prevArray, 4]); // -> [1, 2, 3, 4]

// Remove last entry
setArray(prevArray => prevArray.splice(0, prevArray.length - 1)); // -> [1, 2, 3]

Similar codes

1 vote100 views1 answer
Npm react dropdown
Javascript React
0 vote103 views1 answer
How to download an mp3 file in react native
Javascript React
0 vote109 views1 answer
Export socket io connection in react
Javascript React
1 vote63 views1 answer
Mkdir: cannot create directory â€˜src/components/dashboardâ€™: no such file or directory in react
Javascript React
1 vote105 views1 answer
How prevent copy paste input react
Javascript React
1 vote99 views1 answer
React eslint prettier
Javascript React
0 vote100 views2 answers
React foreach loop
Javascript React
0 vote121 views1 answer
Asp.net core react server session
Javascript React
0 vote113 views1 answer
React change button color on hover
Javascript React
0 vote97 views1 answer
Google-maps-react give undefined lat long
Javascript React