Key value in javascript

This is the continuation of this question which is here How to group by dynamic key value of an object of arrays(Month and year) Here i am getting output as expected but i want a small change on the output. The out put which is producing right now is as follows.
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But the result which i am expecting is goes like this.

enter image description here
Code which i am using is like this.

           //Stack to retrive result
              let filteredStack:any =[];
            //Sorting based on the sorted key
              sortedKeys.forEach(k => {
                filteredStack.push(k,result[k]);
              });

How can i do this?