fix(collection): add to_json and to_yaml for RethinkORM::Collection

Author: caspiano

spec/associations_spec.cr

@@ -80,14 +80,13 @@ describe RethinkORM::Associations do
       car = Car.create!(brand: "Toyota")
       car.persisted?.should be_true
 
-      wheels = [] of Wheel
-      4.times do |v|
-        wheel = Wheel.new(width: 10 + v)
-        wheel.car = car
-        wheel = wheel.save!
-        wheel.persisted?.should be_true
-        car.id.should eq wheel.car_id
-        wheels << wheel
+      wheels = Array.new(4) do |v|
+        Wheel.new(width: 10 + v).tap do |wheel|
+          wheel.car = car
+          wheel = wheel.save!
+          wheel.persisted?.should be_true
+          car.id.should eq wheel.car_id
+        end
       end
 
       # Check the associations can be retrieved

spec/collection_spec.cr

@@ -0,0 +1,24 @@
+require "./spec_helper"
+
+module RethinkORM
+  describe Collection do
+    it "#to_json" do
+      car = Car.create!(brand: "Toyota")
+      car.persisted?.should be_true
+
+      wheel_ids = Array.new(4) do |v|
+        Wheel.new(width: 10 + v).tap do |wheel|
+          wheel.car = car
+          wheel = wheel.save!
+          wheel.persisted?.should be_true
+          car.id.should eq wheel.car_id
+        end.id.as(String)
+      end.sort
+
+      Array(Wheel)
+        .from_json(car.wheels.to_json)
+        .compact_map(&.id).sort!
+        .should eq(wheel_ids)
+    end
+  end
+end

src/rethinkdb-orm/utils/association_collection.cr

@@ -8,7 +8,7 @@ class RethinkORM::AssociationCollection(Owner, Target)
 
   delegate :find, :find!, to: Target
 
-  delegate :each, to: :all
+  delegate :each, :to_yaml, :to_json, to: :all
 
   def initialize(@owner, foreign_key = nil)
     @foreign_key = !foreign_key ? "#{Owner.table_name}_id" : foreign_key.to_s

src/rethinkdb-orm/utils/collection.cr

@@ -50,6 +50,18 @@ module RethinkORM
         end
       end
 
+      def to_json(json : JSON::Builder) : Nil
+        json.array do
+          each(&.to_json(json))
+        end
+      end
+
+      def to_yaml(yaml : YAML::Nodes::Builder) : Nil
+        yaml.sequence(reference: self) do
+          each(&.to_yaml(yaml))
+        end
+      end
+
       def stop
         @iterator.stop
         super