Hi can anyone please help me. I want to be able to generate all possible combinations of the array but only certain elements will be changing given two possible numbers to choose from. Their position is important too.

For example: let arr = [1,2,3, (4 or 5), (6 or 7), (8 or 9)]

I want to generate
1,2,3,4,6,8
1,2,3,4,6,9
1,2,3,4,7,8
.
.
.
.
This goes on until 1,2,3,5,7,9

I know it is very similar to binary numbers, I just don't know how to go about it and also the array may change in size so it can lead to a lot of options and possible outcomes.

Please. Someone help.

Edit: clarified the combinations I want to generate