[JS]Summing Two Number

Here is an array containg numbers. We are going to sum of all possible combinations of two numbers in the array. Simply, we can use nested loops for summing.

var numbers = [3, 9, 4, 12, 7];

for (var i = 0; i < numbers.length; i++) {
  for (var j = i + 1; j < numbers.length; j++) {
    temp.push(numbers[i] + numbers[j]); // temp = [12, 7, 15, 10, 13, 21, 16, 16, 11, 19]
  }
}

The next step is to remove duplicates. You may can use filter() or Set().

// filter()
answer = temp.filter((el, index) => temp.indexOf(el) === index);

// Set()
answer = [...new Set(temp)];

If you want to sort the array temp, you can use sort(). But sort() is for lexicographical order. So, we need to write it this way:

answer.sort((a, b) => a - b);

You can find more information about sort() here

Finally, we’ve got the result

[7, 10, 11, 12, 13, 15, 16, 19, 21]