call mongodb function

Hi guys,

I’m currently learning how to work with yii2 + mongodb.

I already know how to insert a document using \yii\mongodb\collection, example :


$collection->insert(['name' => 'john'])

and know how to find a document, example :


$collection->find(['name' => 'john'])

But i’m stuck about how to call a mongodb function from yii2. Let say I already create this function in my mongodb :


db.system.js.save(

   {

     _id: "echoFunction",

     value : function(x) { return x; }

   }

)

How to call this function from yii2 ?

Any help would be appreciated. Thanks before