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Iterator: Group By

Bucket the elements of a list. The sub-graph runs once per element and emits two values to the auto-created Iterator::Collect:

  • key (String) — the bucket label.
  • value (any) — the element to put in that bucket. When omitted, the original element is used.

The result is a JSON object whose keys are the distinct bucket labels and whose values are arrays of the matching elements. Elements whose sub-graph yields a missing or non-String key are silently dropped (no error). Bucket keys appear in alphabetical order in the output object, not in first-seen order.

Example
Input:  [{name: "alice", team: "A"}, {name: "bob", team: "B"}, {name: "carol", team: "A"}]
Body:   key = el.team, value = el.name
Output:
{
  "A": ["alice", "carol"],
  "B": ["bob"]
}

Parameters​

This function has no parameters.

Input​

Arrayrequired

List to bucket (Array or JSON array).

Value

Optional value injected into every iteration as value on the entry node.

Output​

Result

JSON object — one key per distinct bucket label, each holding an array of the matching values.