Aggregate

Takes an array of values and returns a scalar summary (sum / count / avg / min / max) or a grouped map (groupBy).

When to use

• Reporting nodes: "Total revenue for this batch = sum of amount."
• Summary metrics after a Loop: "How many items passed? How many failed?"
• Grouping a flat list by a category field for downstream per-group processing.

Configuration

Field	Required	What it does
arrayPath	Yes	Data reference pointing to the array to aggregate.
operation	Yes	sum, count, avg, min, max, or groupBy.
field	See table	Which field on each array element to aggregate. Not required for count.
groupByField	See table	Which field to group by. Required only for groupBy.

Operation reference

Operation	Uses field	Returns
sum	Yes	Numeric sum of field across all elements
count	No	Count of elements
avg	Yes	Numeric mean of field
min	Yes	Minimum value of field
max	Yes	Maximum value of field
groupBy	Yes (groupByField)	{ [group]: [...elements] }

What it outputs

{
  value: <the scalar result, or the grouped map>,
  operation: "sum",
  sourceCount: 142
}

Downstream nodes reference {{aggregate.data.value}}.

Example: total revenue by country

Loop results → Aggregate
  arrayPath: {{loop.data.results}}
  operation: groupBy
  groupByField: country
→ Transform
  mappings: [
    { targetKey: "us_total", sourceExpression: "{{agg.data.value.US.length}}" },
    …
  ]

Gotchas

• Non-numeric field with sum/avg/min/max is silently ignored. Check your data shape first.
• Empty array returns { value: 0, … } for numeric ops, [] for groupBy's empty groups.