$function combines "return" and next word/characters when execute the query

[turivishal]

Reference: $function operator from MongoDB v4.4,

Original Code (Working in Mongo Shell):

db.collection.aggregate([
  {
    $addFields: {
      locations: {
        $function: {
          body: function(locations, sort_category){
            return locations.sort(function(a, b){
              return a[sort_category]-b[sort_category]
            })
          },
          args: ["$locations", "$sort_category"],
          lang: "js"
        }
      }
    }
  }
])

Implementation on Playground:
https://mongoplayground.net/p/Jq4JdgDf3K2

Behavior after executing in MongoPlayground :
It will combines return with next word,

db.collection.aggregate([
  {
    $addFields: {
      locations: {
        $function: {
          body: function(locations, sort_category){

            /* below line should be "return locations.sort(function(a, b){" */
            returnlocations.sort(function(a, b){

              /* below line should be "return a[sort_category]-b[sort_category]" */
              returna[sort_category]-b[sort_category]

            })
          },
          args: ["$locations", "$sort_category"],
          lang: "js"
        }
      }
    }
  }
])

[feliixx]

Hi @turivishal

thanks for the detailed report ! This is a bug from the formatter, it doesn't works well with javascript right now :/ I'll try to fix this next week

[turivishal]

@feliixx we are really waiting for this operator to be support in playground.

[feliixx]

Hi @turivishal,

I'm planning to fix this soon, in the meantime I've found that enclosing the whole function in double quote works, but it's ugly as it has to be on a single line:

db.collection.aggregate([
  {
    $addFields: {
      locations: {
        $function: {
          body: "function(locations, sort_category){ return locations.sort(function(a, b){ return a[sort_category]-b[sort_category]})}",
          args: [
            "$locations",
            "$sort_category"
          ],
          lang: "js"
        }
      }
    }
  }
])

see: https://mongoplayground.net/p/CEecvX7XLuH

[turivishal]

@feliixx it will work for now, Thanks.