I am trying to solve a question for interview preparation. I am struggling to find the right data structure and logic to solve this.

The question is as follows

There are inputs array of the format: ["date, item"]. For example:

[["10212021", popcorn], ["10222021", popcorn], ["10212021", soda],["10212021", popcorn],["10212021", soda]]

On the same day if there are popcorn and soda both purchased, then it costs 9 dollars as a bundled price. else soda is 2.5 dollars, popcorn is 8 dollars.

You need to calculate the total price based on these criteria and return that as output.

My initial train of thought

1. Have each item tuple - date and item in a hashtable or dictionary
2. if a corresponding item exists with the same date for the combo apply discount
3. deduct combo price from total

I am a beginner in JS please advise.