If field exist must be true, but if not exist must be pass like true

Question

I would like to check if a field exist in pipeline aggregate (existeTransformacion) . If this field exist must be true to pass ($match) and if is false I need to exclude from my results, but if not exist must be pass. How can I achieve this?

 {
            //...more data
            "ubicacionActual": {
                "transformacion": {
                   "trabajando": true,
                }
            },
            //This field come from $project in this way 
            //$project: {existeTransformacion: '$ubicacionActual.transformacion.trabajando'}
            "existeTransformacion": true,
            "paso": 1
        },

So basically:

• If exist existeTransformacion and existeTransformacion===true must be showing.

• If exist existeTransformacion and existeTransformacion===false must be not showing.

• if not exist must be showing.

Answer 1

You need to use $or and $exists operators

{
  $match: {
    $or: [
      {
        "existeTransformacion": true
      },
      {
        "existeTransformacion": {
          $exists: false
        }
      }
    ]
  }
}

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