Adds default custom scalar of interface{}

codegen/config/config.go

@@ -365,6 +365,7 @@ func (c *Config) InjectBuiltins(s *ast.Schema) {
 	extraBuiltins := TypeMap{
 		"Time": {Model: StringList{"github.com/99designs/gqlgen/graphql.Time"}},
 		"Map":  {Model: StringList{"github.com/99designs/gqlgen/graphql.Map"}},
+		"Any":  {Model: StringList{"github.com/99designs/gqlgen/graphql.Any"}},
 	}
 
 	for typeName, entry := range extraBuiltins {

docs/content/reference/scalars.md

@@ -7,7 +7,7 @@ menu: { main: { parent: 'reference' } }
 
 ## Built-in helpers
 
-gqlgen ships with two built-in helpers for common custom scalar use-cases, `Time` and `Map`.  Adding either of these to a schema will automatically add the marshalling behaviour to Go types.
+gqlgen ships with three built-in helpers for common custom scalar use-cases, `Time`, `Any` and `Map`.  Adding any of these to a schema will automatically add the marshalling behaviour to Go types.
 
 ### Time
 
@@ -25,6 +25,14 @@ scalar Map
 
 Maps an arbitrary GraphQL value to a `map[string]{interface}` Go type.
 
+### Any
+
+```graphql
+scalar Any
+```
+
+Maps an arbitrary GraphQL value to a `interface{}` Go type.
+
 ##  Custom scalars with user defined types
 
 For user defined types you can implement the graphql.Marshal and graphql.Unmarshal interfaces and they will be called.
@@ -75,7 +83,7 @@ models:
 
 ## Custom scalars with third party types
 
-Sometimes you cant add methods to a type because its in another repo, part of the standard 
+Sometimes you cant add methods to a type because its in another repo, part of the standard
 library (eg string or time.Time). To do this we can build an external marshaler:
 
 ```go
@@ -85,7 +93,7 @@ import (
 	"fmt"
 	"io"
 	"strings"
-	
+
 	"github.com/99designs/gqlgen/graphql"
 )
 

graphql/any.go

@@ -0,0 +1,19 @@
+package graphql
+
+import (
+	"encoding/json"
+	"io"
+)
+
+func MarshalAny(v interface{}) Marshaler {
+	return WriterFunc(func(w io.Writer) {
+		err := json.NewEncoder(w).Encode(v)
+		if err != nil {
+			panic(err)
+		}
+	})
+}
+
+func UnmarshalAny(v interface{}) (interface{}, error) {
+	return v, nil
+}