Const ObjectIdScalar
ObjectIdScalar: GraphQLScalarType = new GraphQLScalarType({name: 'ObjectId',description: 'Mongo object id scalar type',parseValue(value: string) {return new Types.ObjectId(value) // value from the client input variables},serialize(value: Types.ObjectId) {return value.toHexString() // value sent to the client},parseLiteral(ast) {if (ast.kind === Kind.STRING) {return new Types.ObjectId(ast.value) // value from the client query}return null}})