Add implicit cache redirect

src/ApolloClient.ts

@@ -27,6 +27,7 @@ import {
 
 import {
   CustomResolverMap,
+  CustomResolver,
 } from './data/readFromStore';
 
 import {
@@ -129,6 +130,9 @@ export default class ApolloClient {
    * @param dataIdFromObject A function that returns a object identifier given a particular result
    * object.
    *
+   * @param defaultIdLookup A function used to find objects in the cache by their key.
+   * Should return an object identifer given a particular result object and arguments.
+   *
    * @param queryTransformer A function that takes a {@link SelectionSet} and modifies it in place
    * in some way. The query transformer is then applied to the every GraphQL document before it is
    * sent to the server.
@@ -149,6 +153,7 @@ export default class ApolloClient {
     reduxRootSelector,
     initialState,
     dataIdFromObject,
+    defaultIdLookup,
     resultTransformer,
     resultComparator,
     ssrMode = false,
@@ -164,6 +169,7 @@ export default class ApolloClient {
     reduxRootSelector?: string | ApolloStateSelector,
     initialState?: any,
     dataIdFromObject?: IdGetter,
+    defaultIdLookup?: CustomResolver,
     resultTransformer?: ResultTransformer,
     resultComparator?: ResultComparator,
     ssrMode?: boolean,
@@ -220,6 +226,7 @@ export default class ApolloClient {
 
     this.reducerConfig = {
       dataIdFromObject,
+      defaultIdLookup,
       mutationBehaviorReducers,
       customResolvers,
     };

src/data/readFromStore.ts

@@ -11,6 +11,7 @@ import {
   NormalizedCache,
   isJsonValue,
   isIdValue,
+  toIdValue,
   IdValue,
 } from './storeUtils';
 
@@ -85,6 +86,7 @@ type ReadStoreContext = {
   returnPartialData: boolean;
   hasMissingField: boolean;
   customResolvers: CustomResolverMap;
+  defaultIdLookup: CustomResolver;
 }
 
 let haveWarned = false;
@@ -146,16 +148,27 @@ const readStoreResolver: Resolver = (
   const fieldValue = (obj || {})[storeKeyName];
 
   if (typeof fieldValue === 'undefined') {
-    if (context.customResolvers && obj && (obj.__typename || objId === 'ROOT_QUERY')) {
+    if (obj && (obj.__typename || objId === 'ROOT_QUERY')) {
       const typename = obj.__typename || 'Query';
 
-      // Look for the type in the custom resolver map
-      const type = context.customResolvers[typename];
-      if (type) {
-        // Look for the field in the custom resolver map
-        const resolver = type[fieldName];
-        if (resolver) {
-          return resolver(obj, args);
+      if (context.customResolvers) {
+
+        // Look for the type in the custom resolver map
+        const type = context.customResolvers[typename];
+        if (type) {
+          // Look for the field in the custom resolver map
+          const resolver = type[fieldName];
+          if (resolver) {
+            return resolver(obj, args);
+          }
+        }
+      }
+
+      if (args && context.defaultIdLookup) {
+        const defaultId = context.defaultIdLookup(obj, args);
+
+        if (defaultId && context.store[defaultId]) {
+          return toIdValue(defaultId);
         }
       }
     }
@@ -201,7 +214,7 @@ export function diffQueryAgainstStore({
     store,
     returnPartialData,
     customResolvers: config && config.customResolvers,
-
+    defaultIdLookup: config && config.defaultIdLookup,
     // Flag set during execution
     hasMissingField: false,
   };

src/store.ts

@@ -43,6 +43,7 @@ import {
 
 import {
   CustomResolverMap,
+  CustomResolver,
 } from './data/readFromStore';
 
 import assign = require('lodash/assign');
@@ -178,6 +179,7 @@ export function createApolloStore({
 
 export type ApolloReducerConfig = {
   dataIdFromObject?: IdGetter;
+  defaultIdLookup?: CustomResolver;
   mutationBehaviorReducers?: MutationBehaviorReducerMap;
   customResolvers?: CustomResolverMap;
 }

test/readFromStore.ts

@@ -1,11 +1,15 @@
+import mockNetworkInterface from './mocks/mockNetworkInterface';
 import { assert } from 'chai';
+import ApolloClient from '../src';
 import assign = require('lodash/assign');
 import omit = require('lodash/omit');
 
 import {
   readQueryFromStore,
 } from '../src/data/readFromStore';
 
+import { NetworkStatus } from '../src/queries/store';
+
 import {
   NormalizedCache,
   StoreObject,
@@ -647,4 +651,58 @@ describe('reading from the store', () => {
       computedField: 'This is a string!5bit',
     });
   });
+
+  it(`does cache lookups when defaultIdLookup is supplied`, () => {
+    const dataIdFromObject = (obj: any) => {
+      return obj.id;
+    };
+
+    const defaultIdLookup = (obj: any, args: any): string => {
+      return args.id;
+    };
+
+    const listQuery = gql`{ people { id name } }`;
+
+    const listData = {
+      people: [
+        {
+          id: '4',
+          name: 'Luke Skywalker',
+          __typename: 'Person',
+        },
+      ],
+    };
+
+    const netListQuery = gql`{ people { id name __typename } }`;
+
+    const itemQuery = gql`{ person(id: 4) { id name } }`;
+
+    // We don't expect the item query to go to the server at all
+    const networkInterface = mockNetworkInterface({
+      request: { query: netListQuery },
+      result: { data: listData },
+    });
+
+    const client = new ApolloClient({
+      networkInterface,
+      dataIdFromObject,
+      defaultIdLookup,
+    });
+
+    return client.query({ query: listQuery }).then(() => {
+      return client.query({ query: itemQuery });
+    }).then((itemResult) => {
+      assert.deepEqual(itemResult, {
+        loading: false,
+        networkStatus: NetworkStatus.ready,
+        data: {
+          person: {
+            __typename: 'Person',
+            id: '4',
+            name: 'Luke Skywalker',
+          },
+        },
+      });
+    });
+  });
 });