Split an array into separate items in Duaer

Split an array with Split Out

1. Add Split Out after the node that holds the array.
2. Set Fields To Split Out to the array field, such as line_items; use data.items for nested paths.
3. Under Include, keep No Other Fields, All Other Fields, or Selected Other Fields for a few, such as the order number.
4. Select Execute step. You get one item per array entry.

When the field is text such as a,b,c, turn it into an array first in Edit Fields with {{ $json.tags.split(",") }}, type Array, then split.

Split with Code and keep parent fields

To rename fields or carry parent data at the same time, use Code (Run Once for All Items):

return $input.all().flatMap((item) =>
  item.json.line_items.map((line) => ({
    json: { order: item.json.name, ...line },
  })),
);

The reverse: combine items into one array

To combine items back into one array or one text, use Aggregate, or Append and Concatenate in Summarize.