Aggregate
Aggregate
Section titled “Aggregate”Fold many items into a single item.
What it does
Section titled “What it does”Takes the whole collection of incoming items and combines it into one item. It is the exact inverse of Split Out: splitting a field out and aggregating it back returns the original array.
There are two modes:
- Individual fields collects one or more chosen fields, across every item, into arrays. Items
[{ price: 3 }, { price: 5 }]aggregated onpriceproduce the single item{ price: [3, 5] }. - All item data wraps every incoming item, whole, under a single named field.
When to use it
Section titled “When to use it”Use this node to act once on a whole list rather than once per row: to send one summary message about a scraped list instead of one per row, to hand a full result set to a model in a single prompt, or to turn “many rows with one value” back into “one row with many values”.
To join two separate branches together on matching keys, use Merge instead — that combines different data about the same things across two inputs, whereas Aggregate folds one input down.
Inputs and settings
Section titled “Inputs and settings”| Setting | Notes |
|---|---|
| Mode | Individual fields collects chosen fields into arrays, All item data wraps every item into one field. Defaults to Individual fields. |
| Fields To Aggregate | (Individual fields mode) The list of fields to collect. Each entry has a Field (dot path, e.g. user.profile.name) and an optional Output field name for the resulting array — this defaults to the last segment of the path, mirroring how Split Out names the field it emits. Empty by default. |
| Put Output In Field | (All item data mode) The name of the field that holds every input item. Defaults to data. |
| Keep Missing Values | Off by default. Off: items that lack the collected field are skipped, so the array is shorter. On: they contribute null, so positions stay aligned across several aggregated fields. |
What counts as missing
Section titled “What counts as missing”Only an absent key — a field path that cannot be reached — is treated as missing. A field that is present but null is collected as a real value. This deliberately differs from Sort, where null and empty strings carry no ordering and sort last.
Outputs
Section titled “Outputs”Returns a single item.
- In Individual fields mode, one field per collected entry, each holding an array of the gathered values.
- In All item data mode, one field (named by Put Output In Field) holding the array of every input item.
Dependencies and credentials
Section titled “Dependencies and credentials”- No credential or node dependency is required. The node runs entirely in the browser.
Example workflow
Section titled “Example workflow”A node returns a list of scraped listings. Connect it into Aggregate in Individual fields mode, add a field title (output name titles) and a field url (output name urls), and the node emits a single item { titles: [...], urls: [...] } that you can drop into one notification message. To round-trip, a Split Out on titles would fan it back into individual items.
Troubleshooting
Section titled “Troubleshooting”- Aggregate operates on the whole collection at once. If it seems to have no effect, make sure the upstream node emits multiple items rather than a single object.
- In Individual fields mode the node reports an error if no field is set — add at least one field, or switch to All item data.
- If an aggregated array is shorter than you expect, some items are missing that field. Turn on Keep Missing Values to contribute
nulland keep the arrays aligned. - Remember that
nullis collected as a real value; only a genuinely absent key is skipped.