Missing field session in {}

[TacticCoder]

export const resolvers = {
	Query: {
		session: (_, variables, { cache }) => {
			try {
				const { session } = cache.readQuery({ query });
				return session;
			} catch (ex) {
				const data = {
					session: {
						id: 'session',
						count: 0,
						__typename: 'session',
					},
				};
				const theData = cache.writeData({ data });
				return theData;
			}
		},
	},
	Mutation: {
		addCartItem: (_, variables, { cache }) => {
			let finalCount = 0;
			const { session } = cache.readQuery({ query });
			finalCount = session.count;
			const data = {
				session: {
					id: 'session',
					count: finalCount + 1,
					__typename: 'session',
				},
			};
			cache.writeData({ data });
			return data;
		},
	},
};

const query = gql`
  query getSession{
	session @client {
		count		
		__typename 
	}
  }
`;

While executing this query above I get an warning:
"Missing field session in {}"
Search on stack and slack but now helpful one.

[TacticCoder]

Solve that, for those who may get in to it at the future, I just needed to add defaults to the withClientState() and use the then() promise while loading the cache,

persistCache({
    cache,
    storage: window.localStorage,
    maxSize: false, // set to unlimited (default is 1MB https://github.com/apollographql/apollo-cache-persist)
    debug: true,     // enables console logging
}).then(() => {
    // Continue setting up Apollo as usual.
    ReactDOM.render( ......