(async () => {

  const result = await client.mutate({

    mutation: gql(createTodo),

    variables: {

      input: {

        name: 'Use AppSync',

        description: 'Realtime and Offline',

      }

    },

    optimisticResponse: () => ({

      createTodo: {

        __typename: 'Todo', // This type must match the return type of the query below (listTodos)

        id: uuid(),

        name: 'Use AppSync',

        description: 'Realtime and Offline',

      }

    }),

    update: (cache, { data: { createTodo } }) => {

      const query = gql(listTodos);

      // Read query from cache

      const data = cache.readQuery({ query });

      // Add newly created item to the cache copy

      data.listTodos.items = [

        ...data.listTodos.items.filter(item => item.id !== createTodo.id),

        createTodo

      ];

      //Overwrite the cache with the new results

      cache.writeQuery({ query, data });

    }

  });

(async () => {

  const result = await client.mutate(buildMutation(client,

    gql(createTodo),

    {

      inputType: gql(CreateTodoInput),

      variables: {

        input: {

          name: 'Use AppSync',

          description: 'Realtime and Offline',

        }

      }

    },

    (_variables) => [ gql(listTodos) ],

    'Todo'));

  console.log(result);

})();