Node JS displaying value at index instead of indices

Written this 2sums code to get efficent O(N) Time complexity algorithm for below problem

            Input: nums = [2,7,11,15], target = 9
            Output: [0,1]
            Output: Because nums[0] + nums[1] == 9, we return [0, 1].

unfortunately saw value at array nums got displayed in the output ,whereas the need is to get the indices to be displayed in output

What change needs to be done below

            let hashTwoSum = (array, sum) => {
                let numsObj = {}
                let nums = []
               
                for(let i in array){
                    let addend = sum - array[i]
                   
                    if (addend in numsObj){

                        nums.push([addend, array[i]])

                    }
                    numsObj[array[i]] = i

                    
                }
                return nums
                
            }

            let array = [2,7,11,15]
            console.log(hashTwoSum(array,9))
            
            

Your help is appreciated

Regards,

Carolyn