a join aggregate must be a non-empty object ...

Warnings reference › data-router:join-aggregate-invalid

Identifier

data-router:join-aggregate-invalid

Raised by

Data Router

Since

1.84.0

What happened

A many: true join was given an aggregate that is not a usable object - empty, or not an object at all. There is nothing to write onto the parent row, so the whole join is dropped and the rows pass through unenriched rather than the router throwing.

The fix

Set aggregate to an object of named reducers: { field: { fn, field? } }, one entry per result you want on the parent row.

The smallest fix

join: { from: 'line', foreignKey: 'orderId', many: true, aggregate: { lines: { fn: 'count' }, lineTotal: { field: 'amount', fn: 'sum' } } }

Reference

Covered in full at the API reference.