Apollo Client Cache

1. ©2018 Wantedly, Inc. Apollo Client Cache meguro.es 2019.10.10 - Naoki Kobayashi
2. ©2018 Wantedly, Inc. Naoki Kobayashi GitHub: @kobayang Twitter: @kbys_02 I’m an Frontend Engineer @Wantedly
3. ©2018 Wantedly, Inc. https://blog.apollographql.com/introducing-the-apollo-graphql-platform-8ef34bb269e5 cache
4. ©2018 Wantedly, Inc. { Declare GraphQL Query Use Query to fetch data const TodoContainer = () => { const { data, loading, error } = useQuery(todosQuery); const todos = data ? data.todos : []; } const todosQuery = gql` query TodosQuery { todos { id title } } `;
5. ©2018 Wantedly, Inc. Agenda • Apollo Client ͷ Cache ͸͍ͭߦΘΕΔ͔ • ͲͷΑ͏ʹCacheͷߋ৽Λߦ͏͔ • ͲΜͳσʔλ͕Cacheʹೖ͍ͬͯΔ͔ • Cacheͷߋ৽ͷ࠷దԽ
6. ©2018 Wantedly, Inc. Fetch Data Flow User Interface Fetch Cache 3FRVFTU
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7. ©2018 Wantedly, Inc. Prefetching Data https://www.apollographql.com/docs/react/performance/performance/ onMouseOver Ͱ query ΛಡࠐΉ LinkઌͰ͸ಉ͡ΫΤϦΛಡࠐΉͱ Cache͕ώοτ͢ΔͨΊɺ Loadingͳ͠ͰData͕࢖͑Δ
8. ©2018 Wantedly, Inc. Local State Management https://www.apollographql.com/docs/react/performance/performance/ • CacheΛར༻ͯ͠LocalͷStateΛѻ͑Δ • @client directive Λ Query/Mutation ʹ
 ͚ͭΔ͜ͱͰऔಘઌ͕ϩʔΧϧʹͳΔ # local-schema.grpahql extend type Todo { done: Boolean! } // apollo.ts const resolvers: Resolvers = { Todo: { done(todo: TodoFragment) { return todo.done || false; }, }, }; const todoFragment = gql` fragment TodoFragment on Todo { id title done @client } `;
9. ©2018 Wantedly, Inc. InMemoryCache https://medium.com/expedia-group-tech/creating-your-own-apollo-cache-for-perf-and-profit-8f786849e5f6 • ApolloClientͷΩϟογϡͷσϑΥϧτ࣮૷ • Ωϟογϡ͢ΔࡍʹσʔλΛਖ਼نԽ͢Δ(Normalize)
10. ©2018 Wantedly, Inc. Mutation Data Flow User Interface Mutation Apollo Server Cache 3FRVFTU
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11. ©2018 Wantedly, Inc. Mutation Data Flow User Interface Mutation Apollo Server Cache 3FRVFTU
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12. ©2018 Wantedly, Inc. ྫ: Todoͷ௥Ճ BEE5PEP.VUBUJPO UPEPT2VFSZ const todosQuery = gql` query TodosQuery { todos { id title } } `;
13. ©2018 Wantedly, Inc. ྫ: refetchQueries const addTodoMutation = gql` mutation AddTodoMutation($title: String!) { addTodo(title: $title) { id title } } `; const [addTodo] = useMutation(addTodoMutation, { refetchQueries: [{ query: todosQuery }], }); Cache 3FGFUDI 4FSWFS
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14. ©2018 Wantedly, Inc. ྫ: update const [addTodo] = useMutation(addTodoMutation, { update: (cache, { data }) => { const cachedQuery = cache.readQuery({ query: todosQuery }); if (!cachedQuery || !data) { throw new Error(); } const todos = cachedQuery.todos; cache.writeQuery({ query: todosQuery, data: { todos: todos.concat([data.addTodo]) }, }); }, }); 4FSWFS
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15. ©2018 Wantedly, Inc. ΩϟογϡΛ೷͍ͯΈΔ Apollo Client Developer Tools: Ωϟογϡͷத਎Λ֬ೝͰ͖Δ
16. ©2018 Wantedly, Inc. dataIdFromObject https://github.com/apollographql/apollo-client/blob/22a450aace/packages/apollo-cache-inmemory/src/inMemoryCache.ts
17. ©2018 Wantedly, Inc. readFragment const data = client.readFragment<TodoFragment>({ id: "Todo:1", fragment: todoFragment, }); console.log(data); // => { id: 1, title: "ൃදࢿྉΛ࡞Δ", __typename: "Todo" }
18. ©2018 Wantedly, Inc. id͕ͳ͍৔߹ • ROOT_QUERY.todos.0 ͷΑ͏ʹ 
 ROOT_QUERY ʹඥ͍ͮͯΩϟογϡ͞ΕΔ const todosQuery = gql` query TodosQuery { todos { title } } `;
19. ©2018 Wantedly, Inc. id͕ͳ͍৔߹ • ࣮͸readFragmentͰऔಘͰ͖Δ const data = client.readFragment<TodoFragment>({ id: “ROOT_QUERY.todos.0”, fragment: todoFragment, }); console.log(data); // => { title: "ൃදࢿྉΛ࡞Δ", __typename: "Todo" }
20. ©2018 Wantedly, Inc. Mutation Data Flowʢ࠶ܝʣ User Interface Mutation Apollo Server Cache 3FRVFTU
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21. ©2018 Wantedly, Inc. Optimistic Response Mutation Apollo Server Cache User Interface Optimistic Response
22. ©2018 Wantedly, Inc. Optimistic Response Mutation ͷҾ਺ʹ௥Ճ optimisticResponse: vars => ({ addTodo: { id: "-1", title: vars.title, __typename: "Todo", }, }), update: (cache, { data }) => { console.log("update", data); //… } update͸mutation࣮ߦ࣌ͱߋ৽࣌ʹ 2ճݺ͹ΕΔ
23. ©2018 Wantedly, Inc. Optimistic Response ApolloCache removeOptimistic Ͱ optimisticResponseͷΩϟογϡ͸࡟আ͞ΕΔ https://github.com/apollographql/apollo-client/blob/22a450aace/packages/apollo-cache-inmemory/src/inMemoryCache.ts#L251
24. ©2018 Wantedly, Inc. ·ͱΊ • Apollo Clientʹ͸Ωϟογϡͷ࢓૊Έ͕͋Γ
 Fetchͨ͠σʔλΛਖ਼نԽͯ͠Ωϟογϡ͍ͯ͠Δ
 • Mutation࣌͸ɺঢ়گʹ߹Θͤͯ refetchQueries, update, optimisticResponse Λ࣮૷ͯ͠ΩϟογϡΛߋ৽ͤ͞Δඞཁ͕͋Δ
 • ΩϟογϡΛҙࣝ͢Δ͜ͱͰύϑΥʔϚϯεΛ޲্ͤ͞Δ͜ͱ͕Ͱ͖Δ