Here is my code for reference. I'm getting error for line 9 and 10. Is there a way to assign values for dictionary inside an initially empty dictionary :

function anticlockwiseRotate(arr){
            //store the index of elements in a dict
            let index={};
            for(let i=0;i<3;i++){
                for(let j=0;j<3;j++){
                    if(!index.hasOwnProperty(arr[i][j]['x']) && !index.hasOwnProperty(arr[i][j]['y'])){
                        //left shift by 2 and change rowInde)
                        //left shift by 2 and change rowIndex->columnIndex 
                        index[arr[i][j]]['x'] = (Math.abs(j-2));
                        index[arr[i][j]]['y']=i;
                    }
                }
            }
            let rotatedArr= [];
            for(let idx in index){
                rotatedArr[index[idx][x]][index[idx][y]]=idx;
            }
            return rotatedArr
        }
        console.log(anticlockwiseRotate([[1,2,3],[4,5,6],[7,8,9]]))