// Using hooks

​

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

​

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

this.setState(prevState => ({

  myArray: [...prevState.myArray, "new value"]

}))

​

// Save search term state to React Hooks with spread operator and wrapper function

​

// Using .concat(), no wrapper function (not recommended)

setSearches(searches.concat(query))

​

// Using .concat(), wrapper function (recommended)

setSearches(searches => searches.concat(query))

​

// Spread operator, no wrapper function (not recommended)

setSearches([...searches, query])

​

// Spread operator, wrapper function (recommended)

setSearches(searches => [...searches, query])

this.setState({ myArray: [...this.state.myArray, 'new value'] }) //simple value

this.setState({ myArray: [...this.state.myArray, ...[1,2,3] ] }) //another array

​

this.setState(prevState => ({

  myArray: ["new value", ...prevState.myArray]

}))

​

this.setState(prevState => ({

  arrayvar: [...prevState.arrayvar, newelement]

}))

​

​

this.setState(prevState => ({

  myArray: [...prevState.myArray, {"name": "object"}]

}))

​

this.setState(previousState => ({

    myArray: [...previousState.myArray, 'new value']

}));

this.setState(prevState => ({

  myArray: [ {"name": "object"}, ...prevState.myArray]

}))

​

var joined = this.state.myArray.concat('new value');

this.setState({ myArray: joined })

​

​