bottie | Simple BotKit bot with NLP | Bot library

There are a number of ways this can be achieved. One approach would be construct a mapping via the Array#reduce method, which maps each type to the corresponding item with count data included by the following (note that the use of a mapping like this is an optimisation):

• iterate your input array
• for each iteration, reduce the input to an mapping where the key of the map is the item type, and the value is the item (with count)
• if a value for type key is found in the mapping, increment the count of the matching item
• if a value for type key is not found in the mapping, insert a clone of the current item being iterated in reduce(), with an initial count of 1 included for that item
• Pass the mapping created by reduce() to Object.values() to extract a flat Array of the items with corresponding counts computed during the reduction

Here's a working snippet to show this in action: