UPROPERTY

Javascript is not a strict-typed language, so type-info is passed using javascript comment block. property-name/*PropertyFlag+PropertyFlag+type*/

class MyTestActor extends Actor {
  properties() {
    this.replicated_int_var/*Replicated+int*/;
    this.health/*EditAnywhere+ReplicatedUsing:OnRepHealth+int*/;
    this.series/*EditAnywhere+int[]*/;
  }

  MyNiceSum(a/*int*/,b/*float*/,$/*Return+float*/) { 
    return a+b 
  }
  
  MyComplexReturn(a/*out+int*/,$/*ret+int*/) {
    return {
      $:1,
      a:2
    }
  }
}

PropertyFlag	Description
Const
Return
Out
Replicated
NotReplicated
ReplicatedUsing	ReplicatedUsing:rep-notify-function-name
Transient
DuplicateTransient
EditFixedSize
EditAnywhere
EditDefaultsOnly
EditInstanceOnly
BlueprintReadOnly
BlueprintReadWrite
Instanced
GlobalConfig
Config
TextExportTransient
NonPIEDuplicateTransient
Export
EditFixedSize
NotReplicated
NonTransactional
BlueprintAssignable
SimpleDisplay
AdvancedDisplay
SaveGame
AssetRegistrySearchable
Interp
NoClear
VisibleAnywhere
VisibleInstanceOnly
VisibleDefaultsOnly
Category	Category:your-category
DisplayName	DisplayName:your-nice-name