flatMap¶

Flatten an array field into separate messages, each containing a single element of the array.

Parameters¶

Parameter	Type	Description
`field`	string	Path to the array field to be flattened (e.g., `{{row.samples}}`).
`dest`	string	Optional name of the field to store the flattened element (defaults to the same field name).
`keep`	bool	If `true`, keep the original array alongside the flattened messages.

- flatMap:
    field: "{{row.samples}}"
    dest: sample

Given an input message:

{ "id": "P001", "samples": ["S1", "S2", "S3"] }

The step emits three messages:

{ "id": "P001", "sample": "S1" }
{ "id": "P001", "sample": "S2" }
{ "id": "P001", "sample": "S3" }