complex-mutation.jsx

const SUBMIT_COMMENT_MUTATION = gql`
  mutation submitComment($repoFullName: String!, $commentContent: String!) {
    submitComment(repoFullName: $repoFullName, commentContent: $commentContent) {
      postedBy {
        login
        html_url
      }
      createdAt
      content
    }
  }
`;

// used to update the Comment query after the muation runs
const updateQueries = {
  Comment: (prev, { mutationResult }) => {
    const newComment = mutationResult.data.submitComment;
    return update(prev, {
      entry: { comments: { $unshift: [newComment] } },
    });
  },
};

const CommentsPageWithMutations = graphql(SUBMIT_COMMENT_MUTATION, {
  props: ({ ownProps, mutate }) ({
    submit: ({ repoFullName, commentContent }) => mutate({
      variables: { repoFullName, commentContent },
      optimisticResponse: {
        __typename: 'Mutation',
        submitComment: {
          __typename: 'Comment',
          postedBy: ownProps.currentUser,
          createdAt: +new Date,
          content: commentContent,
        },
      },
      updateQueries,
    });
  }),
})(CommentsPage);

here it is
https://github.com/apollographql/GitHunt-React/blob/master/ui/routes/CommentsPage.js#L170-L171