verwijder 0-waarden als 0 wordt gevolgd door>=1 uit arrays in MongoDB

Een benadering is deze:

db.collection.aggregate([
   {
      $set: {
         data: {
            $let: {
               vars: {
                  val: "$data_start",
                  prev: { $concatArrays: [[null], "$data_start"] } // shift values by one element 
               },
               in: {
                  $map: {
                     input: { $range: [0, { $size: "$$val" }] },
                     as: "idx",
                     in: {
                        $cond: {
                           if: {
                              $and: [
                                 { $eq: [{ $arrayElemAt: ["$$val", "$$idx"] }, 0] }, // is 0
                                 { $eq: [{ $arrayElemAt: ["$$val", "$$idx"] }, { $arrayElemAt: ["$$prev", "$$idx"] }] } // is equal to previous
                              ]
                           },
                           then: null,
                           else: {
                              data_start: { $arrayElemAt: ["$$val", "$$idx"] },
                              time_start: { $arrayElemAt: ["$time_start", "$$idx"] }
                           }
                        }
                     }
                  }
               }
            }
         }
      }
   },
   {
      $set: {
         data: {
            $filter: {
               input: "$data",
               cond: "$$this"// -> removes null's from array
            }
         }
      }
   }
])

Misschien moet je de conditie verfijnen en/of de lus omkeren, bijv. input: { $range: [{ $size: "$$val" }, 0, -1] }

Mongo-speeltuin