- const new_squares = this.state.squares.map(arr => arr.slice());
- new_squares[mini_grid_index][position] = {
+ const new_mini_grids = this.state.mini_grids.map(obj => {
+ const new_obj = {...obj};
+ new_obj.squares = obj.squares.slice();
+ return new_obj;
+ });
+ new_mini_grids[mini_grid_index].squares[position] = {