[{"_id":ObjectId("62bf0b8b4feee27711d65e0f"),"files":[],"stages":[{"name":"Documents","updatedAt":ISODate("2022-07-01T14:58:19.108Z"),"state":"none"},{"name":"Registry","state":"none","subStages":[{"name":"name1","completed":false},{"name":"name2","completed":false},{"name":"name3","completed":false}],"updatedAt":ISODate("2022-07-01T14:58:19.108Z"),}]}]

db.collection.update({},[{$set:{stages:{$map:{input:{$ifNull:["$stages",[]]},in:{$cond:["$$this.subStages",{name:"$$this.name",state:"$$this.state",sites:[{/**where should this come from,*/status:"$$this.state",completed:{$allElementsTrue:"$$this.subStages.completed"},/**where should this come from,*/name:"site1",subStages:"$$this.subStages"}]},"$$this"]}}}}}],{"multi":false,"upsert":false})