react update object in array state code example

Example 1: how to update react state array

const [myArray, setMyArray] = useState([1,2,3])

// to update
setMyArray([...myArray, 4]); // --> myArray = [1,2,3,4]

Example 2: how to update array in react state

this.setState(prevState => ({
  arrayvar: [...prevState.arrayvar, newelement]
}))

Example 3: update object in array state by index

this.setState(({items}) => ({
    items: [
        ...items.slice(0,1),
        {
            ...items[1],
            name: 'newName',
        },
        ...items.slice(2)
    ]
}));

Example 4: react native update state array of objects

let newMarkers = markers.map(el => (
      el.name==='name'? {...el, key: value}: el
))
this.setState({ markers });

Tags:

Misc Example

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