Find array elements adding up to given sum

Example 1:
        Input: nums = [2,7,11,15], target = 9
        Output: [0,1]
        Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].
       
Solution
        Brute Force:
            let num_array = [2, 7, 11, 15];
            let target = 9;
            
            let index_1, index_2 = findIndicesAddingToTarget(num_array)
            
            function findIndicesAddingToTarget(num_array) {
              for (let i = 0; i < num_array.length; i++) {
                for (let j = 0; j < num_array.length; j++) {
                  if (i !== j) {
                    if (num_array[i] + num_array[j] === target) {
                      console.log(`indices ${i} and ${j} are adding up to target`);
                      return i,j
                    }
                  }
                }
              }
            }