`onUpdate` method of `FireCollection/FireSubCollection` should contain params in `WriteOptions`. so we can do ``` onUpdate(object: any, { write, params }: WriteOptions) { const ref = doc(this.db, `collection/${params.parentId}/subcollection/${object.id}`); } ``` Possible resolution (not tested) : https://github.com/dappsnation/ngfire/blob/master/libs/ngfire/firestore/src/collection.ts#LL426C15-L426C61 and https://github.com/dappsnation/ngfire/blob/master/libs/ngfire/firestore/src/collection.ts#L447 ``` await this.onUpdate(data, { write: tx, ctx, params: options.params }); ```