React Hooks useState 数组存储问题

Question

I have the following problem: I have a method that returns a multidimensional array in my Grids component. I would want to store any multidimensional array recomputed in a separate list. The problem is that when I am using my useState() declared in this way

const [listGrid,setListGrid] = useState<any[]>([])  

only the current state element is saved repeatedly in the array list. Follow the code of interest part :

const [listGrid,setListGrid] = useState<any[]>([]);
const grid= initGrid(); //initialise a new grid.
 const disableButtonHandler = ():void => {
       const cloneGrid =[...grid]
      console.log(cloneGrid===grid)//are no the same!!
      setListGrid(prevListGrid=>[...prevListGrid,cloneGrid]);
};

this is the snapshot of my list with the grids saved:

so, basically, all the arrays stored in listGrid are the same and I'd want to store any change of my computed list.

what could I do wrong with it? thanks in advance.

Answer 1

The matrix is represented by an array of arrays, while you are duplicating the containing array, the contained ones are still the same. Basically, cloneGrid[i] === grid[i] is true for 0 <= i < grid.length .

You can solve this by doing the following:

const cloneGrid = grid.map(row => [...row]);