Correct way to push into state array

I seem to be having issues pushing data into a state array.
I am trying to achieve it this way:

this.setState({ myArray: this.state.myArray.push('new value') })

But I believe this is incorrect way and causes issues with mutability?

Functional Components & React Hooks

const [array,setArray] = useState([]);

Push value at the end:

setArray(oldArray => [...oldArray,newValue] );

Push value at the start:

setArray(oldArray => [newValue,...oldArray] );

Stack Overflow Q#37435334, score: 246