Doctrine\MongoDB\Aggregation\Stage\Group::addToSet PHP Method

AddToSet is an accumulator operation only available in the group stage.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/addToSet/

See also: Expr::addToSet

public addToSet ( mixed \| Expr $expression ) : Operator
$expression	mixed \| Doctrine\MongoDB\Aggregation\Expr
return	Operator

    public function addToSet($expression)
    {
        $this->expr->addToSet($expression);
        return $this;
    }

Group