#groupBy

Groups an array’s elements by a selected value into key and results pairs.

#groupBy(array, @x: key)

Category Grouping and aggregationValid in Property value

Parameters

Name	Type	Description
array	path | array	The source array.
key	lambda	Selects the grouping value.

Returns

array — An array of { key, results } objects.

Examples

Group by a property

source.json

{
    "someArray": [
        { "groupingProperty": "A", "valueProperty": 1 },
        { "groupingProperty": "A", "valueProperty": 2 },
        { "groupingProperty": "B", "valueProperty": 3 }
    ]
}

transformer.json

{
    "groupedArray": "#groupBy($.someArray, @x: @x.groupingProperty)"
}

output.json

{
    "groupedArray": [
        {
            "key": "A",
            "results": [
                { "groupingProperty": "A", "valueProperty": 1 },
                { "groupingProperty": "A", "valueProperty": 2 }
            ]
        },
        {
            "key": "B",
            "results": [ { "groupingProperty": "B", "valueProperty": 3 } ]
        }
    ]
}

Try it in the playground →

Related

#summarizeWith · #distinct