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Say I have a map that emits the following objects

{"basePoints": 2000, "bonusPoints": 1000}
{"basePoints": 1000, "bonusPoints": 50}
{"basePoints": 10000, "bonusPoints": 5000}

How could I write a reduce in Erlang (not javascript) that would return an aggregate object like this:

{"basePoints": 13000, "bonusPoints": 6050}

(I would rather not have to write 2 separate views that emits each value separately if I can help it)

Many Thanks!

user1149843
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1 Answers1

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You actually do not need special reduce, in this case you can use standard _sum, since it’s able to sum not only numbers, but also arrays of numbers.

Just emit [basePointsNum, 0] for basePoints and [0, bonusPointsNum] for bonusPoints. Or if you have both fields in one doc you might emit [basePointsNum, bonusPointsNum].

After reducing using built-in _sum you will receive an array of two numbers, each is a sum of appropriate index column. This feature seems to be undocumented, however works for both CouchDB and PouchDB, and it’s blazing fast.

ermouth
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