How to filter on aggregated data in Foundry Functions?-CodePudding

I would like to know how can I filter on grouped data in Foundry Functions. I already managed to group and aggregate on my data, see below:

@Function()
    public async grouping(lowerBound : Integer ): Promise<TwoDimensionalAggregation<string>> {
        let grouping = Objects.search()
            .HospitalLosAnalysis()
            .groupBy(val => val['primaryHospitalName'].topValues())
            .count()

        //FILTER SHOULD BE HERE

        return grouping
    }

Now, I would like to filter only on rows, where the count is bigger than parameter lowerBound. The problem is I am not able to filter anymore as the grouping returns a TwoDimensionalAggregation, on which I am not able to filter anymore.

Some context: I would like to create a chart in Workshop where the user would be able to look only at hospitals with a significant count. He would input the lowerBound parameter in a textbox, and the function would remove all of the rows that are smaller than lowerBound.

CodePudding user response：

You should be able to loop through the grouping variable. You can always check what is inside with an old console.log(grouping) and then preview.

It should look something like:

let newBuckets = [];
grouping.buckets.forEach(bucket => {
     if (bucket.value > lowerBound) {
         newBuckets = bucket
     }
});

grouping.buckets = newBuckets;

don't forget to add an await on your let grouping = await Objects.search..etcetc..count()

CodePudding user response：

Assuming what you're looking for here is to filter on the result of the aggregation - otherwise, just filter the incoming data first before aggregating.

Once you've done your TwoDimensionalAggregation, you'll have a typescript data structure of that is a list of "buckets" where each bucket has a key and a value property. The key can be complex (i.e. if you groupBy a numeric, date, or timestamp property and have a range for a key) or simple, as in your case, where the key would be the primaryHospitalName.

So you'll have something like:

`grouping.buckets[0].key === "hospitalName1"`
`grouping.buckets[0].value === N`

You can easily filter this list of buckets any number of ways: something trivial like:

const filteredGrouping = {
    buckets = grouping.buckets.filter(e => e.value >= lowerBound)
}

Then return filteredGrouping instead of grouping. There's potentially relevant documentation about how to Create a custom aggregation here: [your Foundry instance]/workspace/documentation/product/functions/create-custom-aggregations.