All files / src/core QueryManager.ts

92.17% Statements 412/447
88.41% Branches 206/233
94.12% Functions 80/85
91.65% Lines 362/395
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 110710x                                       10x               10x   469x 252x 252x 252x 252x 252x 252x 252x 252x 252x 252x 252x 252x   10x 70x 70x 70x 1x   69x 69x 69x 68x 68x         68x 68x 129x 129x 43x 43x 54x             129x   68x 68x               68x 68x   68x   61x                     61x 61x               61x 61x 61x 5x 4x 4x   1x           61x     7x 7x 7x 7x 7x         61x 61x 5x   61x         10x 308x 308x 308x   308x 308x 245x         245x 245x 245x   308x 308x 308x       308x 308x                     308x 308x 308x 308x 46x 46x 46x   308x 265x             35x 12x     23x 23x 21x 21x 21x   23x 23x         265x 262x     46x   10x 240x 240x 240x 925x 925x 188x 737x 737x 737x     737x     737x   737x     737x     737x   737x     436x       29x       29x 29x 29x 29x                                       407x 407x 407x 407x 332x 332x 332x     75x             75x 75x           75x 75x     407x 407x 9x               398x             407x     3x   407x 407x         407x 384x 384x                 407x                             10x 236x 236x 1x   235x 234x   60x 60x   234x 103x   234x 234x           10x 76x 76x 1x   75x 2x   73x 2x   71x     71x     71x 71x 71x 71x 71x     61x 61x     9x 9x     71x   10x 317x 317x 317x   10x 185x 185x 185x   10x 244x 244x 244x           10x 308x 308x 308x 56x 308x         716x 716x 716x 514x 514x 379x     716x     716x     308x   10x 336x           10x 328x   10x 174x 174x 174x 121x 121x 121x     10x 117x 117x   117x 117x 117x 117x 87x 105x       10x 12x 12x 6x 6x   12x 12x 11x 11x 9x   12x 12x 12x 12x 12x 12x 12x 3x 9x 9x 6x   9x   12x 12x   10x 240x 240x 25x 240x   10x 7x 7x 7x 7x 7x           7x 7x 8x 8x 7x   10x 10x 10x 11x 11x       2x 2x 2x       7x   8x 5x 5x 5x         10x 185x 185x   10x 185x   10x 29x 29x 29x 24x     5x 5x       5x 5x         2x     3x         10x   10x 10x 10x     10x         10x 10x 10x           10x 974x 974x 974x 1568x 481x 1087x 943x   943x       10x 265x 265x 265x 265x           265x     265x 265x 265x   255x 255x 248x 248x     2x 2x   246x 246x 246x   253x 12x     12x   241x 5x   241x 5x     236x 236x                   12x     235x 235x                   265x   10x 4x 4x 4x 1x 1x     3x 2x 2x 2x     10x 308x 308x 308x   10x 6337x   10x 4089x 4089x 4089x   10x 1740x 1740x 14x     10x                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
import {
  execute,
  ApolloLink,
  Operation as Request,
  FetchResult,
} from 'apollo-link-core';
import { ExecutionResult, DocumentNode } from 'graphql';
import { print } from 'graphql/language/printer';
import Deduplicator from 'apollo-link-dedup';
import { DiffResult } from 'apollo-cache-core';
import {
  assign,
  getDefaultValues,
  getMutationDefinition,
  getOperationDefinition,
  getOperationName,
  getQueryDefinition,
  isProduction,
  maybeDeepFreeze,
} from 'apollo-utilities';
 
import { QueryScheduler } from '../scheduler/scheduler';
 
import { isApolloError, ApolloError } from '../errors/ApolloError';
 
import { Observer, Subscription, Observable } from '../util/Observable';
 
import { QueryWithUpdater, DataStore } from '../data/store';
import { MutationStore } from '../data/mutations';
import { QueryStore, QueryStoreValue } from '../data/queries';
 
import {
  WatchQueryOptions,
  SubscriptionOptions,
  MutationOptions,
} from './watchQueryOptions';
import { ObservableQuery } from './ObservableQuery';
import { NetworkStatus, isNetworkRequestInFlight } from './networkStatus';
import { QueryListener, ApolloQueryResult, FetchType } from './types';
 
export interface QueryInfo {
  listeners: QueryListener[];
  invalidated: boolean;
  newData: ApolloQueryResult<any> | null;
  document: DocumentNode | null;
  lastRequestId: number | null;
  // A map going from queryId to an observer for a query issued by watchQuery. We use
  // these to keep track of queries that are inflight and error on the observers associated
  // with them in case of some destabalizing action (e.g. reset of the Apollo store).
  observableQuery: ObservableQuery<any> | null;
  cancel?: (() => void);
}
 
const defaultQueryInfo = {
  listeners: [],
  invalidated: false,
  document: null,
  newData: null,
  lastRequestId: null,
  observableQuery: null,
};
 
export class QueryManager {
  public scheduler: QueryScheduler;
  public link: ApolloLink;
  public mutationStore: MutationStore = new MutationStore();
  public queryStore: QueryStore = new QueryStore();
  public dataStore: DataStore;
 
  private deduplicator: ApolloLink;
  private queryDeduplication: boolean;
 
  private onBroadcast: () => void;
 
  // XXX merge with ObservableQuery but that needs to be expanded to support mutations and
  // subscriptions as well
  private queries: Map<string, QueryInfo> = new Map();
  private idCounter = 1; // let's not start at zero to avoid pain with bad checks

  // A map going from a requestId to a promise that has not yet been resolved. We use this to keep
  // track of queries that are inflight and reject them in case some
  // destabalizing action occurs (e.g. reset of the Apollo store).
  private fetchQueryPromises: {
    [requestId: string]: {
      promise: Promise<ApolloQueryResult<any>>;
      resolve: (result: ApolloQueryResult<any>) => void;
      reject: (error: Error) => void;
    };
  } = {};I

  // A map going from the name of a query to an observer issued for it by watchQuery. This is
  // generally used to refetches for refetchQueries and to update mutation results through
  // updateQueries.
  private queryIdsByName: { [queryName: string]: string[] } = {};

  constructor({
    link,
    queryDeduplication = false,
    store,
    onBroadcast = () => undefined,
    ssrMode = false,
  }: {
    link: ApolloLink;
    queryDeduplication?: boolean;
    store: DataStore;
    onBroadcast?: () => void;
    ssrMode: boolean;
  }) {
    this.link = link;
    this.deduplicator = ApolloLink.from([new Deduplicator(), link]);
    this.queryDeduplication = queryDeduplication;
    this.dataStore = store;
    this.onBroadcast = onBroadcast;
 
    this.scheduler = new QueryScheduler({ queryManager: this, ssrMode });
  }
 
  public mutate<T>({
    mutation,
    variables,
    optimisticResponse,
    updateQueries: updateQueriesByName,
    refetchQueries = [],
    update: updateWithProxyFn,
    errorPolicy = 'ignore',
  }: MutationOptions): Promise<FetchResult<T>> {
    if (!mutation) {
      throw new Error(
        'mutation option is required. You must specify your GraphQL document in the mutation option.',
      );
    }
 
    const mutationId = this.generateQueryId();
    mutation = this.dataStore.getCache().transformDocument(mutation);
 
    variables = assign(
      {},
      getDefaultValues(getMutationDefinition(mutation)),
      variables,
    );
 
    const mutationString = print(mutation);
    const request = {
      query: mutation,
      variables,
      operationName: getOperationName(mutation) || undefined,
    } as Request;
 
    this.setQuery(mutationId, () => ({ document: mutation }));
 
    // Create a map of update queries by id to the query instead of by name.
    const generateUpdateQueriesInfo: () => {
      [queryId: string]: QueryWithUpdater;
    } = () => {
      const ret: { [queryId: string]: QueryWithUpdater } = {};
 
      if (updateQueriesByName) {
        Object.keys(updateQueriesByName).forEach(queryName =>
          (this.queryIdsByName[queryName] || []).forEach(queryId => {
            ret[queryId] = {
              updater: updateQueriesByName[queryName],
              query: this.queryStore.get(queryId),
            };
          }),
        );
      }
 
      return ret;
    };
 
    this.mutationStore.initMutation(mutationId, mutationString, variables);
    this.dataStore.markMutationInit({
      mutationId,
      document: mutation,
      variables: variables || {},
      updateQueries: generateUpdateQueriesInfo(),
      update: updateWithProxyFn,
      optimisticResponse,
    });
 
    this.broadcastQueries();
 
    return new Promise((resolve, reject) => {
      let storeResult: FetchResult<T> | null;
      execute(this.link, request).subscribe({
        next: (result: ExecutionResult) => {
          if (result.errors && errorPolicy === 'none') {
            const error = new ApolloError({
              graphQLErrors: result.errors,
            });
 
            this.mutationStore.markMutationError(mutationId, error);
            this.dataStore.markMutationComplete(mutationId);
            this.broadcastQueries();
            this.setQuery(mutationId, () => ({ document: undefined }));
            reject(error);
            return;
          }
 
          this.mutationStore.markMutationResult(mutationId);
 
          this.dataStore.markMutationResult({
            mutationId,
            result,
            document: mutation,
            variables: variables || {},
            updateQueries: generateUpdateQueriesInfo(),
            update: updateWithProxyFn,
          });
          this.dataStore.markMutationComplete(mutationId);
          this.broadcastQueries();
 
          refetchQueries.forEach(refetchQuery => {
            if (typeof refetchQuery === 'string') {
              this.refetchQueryByName(refetchQuery);
              return;
            }
 
            this.query({
              query: refetchQuery.query,
              variables: refetchQuery.variables,
              fetchPolicy: 'network-only',
            });
          });
 
          storeResult = result as FetchResult<T>;
        },
        error: (err: Error) => {
          this.mutationStore.markMutationError(mutationId, err);
          thIis.dataStore.markMutationComplete(mutationId);
          this.broadcastQueries();
 
          this.setQuery(mutationId, () => ({ document: undefined }));
          reject(
            new ApolloError({
              networkError: err,
            }),
          );
        },
        complete: () => {
          this.setQuery(mutationId, () => ({ document: undefined }));
          if (errorPolicy === 'ignore' && storeResult && storeResult.errors) {
            delete storeResult.errors;
          }
          resolve(storeResult as FetchResult<T>);
        },
      });
    });
  }
 
  public fetchQuery<T>(
    queryId: string,E
    options: WatchQueryOptions,
    fetchType?: FetchType,
    // This allows us to track if this is a query spawned by a `fetchMore`
    // call for another query. We need this data to compute the `fetchMore`
    // network status for the query this is fetching for.
    fetchMoreForQueryId?: string,
  ): Promise<FetchResult<T>> {
    const {
      variables = {},
      metadata = null,
      fetchPolicy = 'cache-first', // cache-first is the default fetch policy.
    } = options;
 
    const query = this.dataStore.getCache().transformDocument(options.query);

    let storeResult: any;
    let needToFetch: boolean = fetchPolicy === 'network-only';
 
    // If this is not a force fetch, we want to diff the query against the
    // store before we fetch it from the network interface.
    // TODO we hit the cache even if the policy is network-first. This could be unnecessary if the network is up.
    if (fetchType !== FetchType.refetch && fetchPolicy !== 'network-only') {
      const { isMissing, result } = this.dataStore.getCache().diffQuery({
        query,
        variables,
        returnPartialData: true,
        optimistic: false,
      });
 
      // If we're in here, only fetch if we have missing fields
      needToFetch = isMissinIg || fetchPolicy === 'cache-and-network';
      storeResult = result;
    }

    const shouldFetch =
      needToFetch && fetchPolicy !== 'cache-only' && fetchPolicy !== 'standby';
 
    const requestId = this.generateRequestId();
 
    // Initialize query in store with unique requestId
    this.setQuery(queryId, () => ({
      document: query,
      lastRequestId: requestId,
    }));
 
    // set up a watcher to listen to cache updates
    this.updateQueryWatch(queryId, options);
 
    this.queryStore.initQuery({
      queryId,
      queryString: print(query),
      document: query,
      storePreviousVariables: shouldFetch,
      variables,
      isPoll: fetchType === FetchType.poll,
      isRefetch: fetchType === FetchType.refetch,
      metadata,
      fetchMoreForQueryId,
    });
 
    // XXX can we batch query updates here?
    this.invalidate(true, queryId, fetchMoreForQueryId);
 
    this.broadcastQueries();
 
    // If there is no part of the query we need to fetch from the server (or,
    // fetchPolicy is cache-only), we just write the store result as the final result.
    const shouldDispatchClientResult =
      !shouldFetch || fetchPolicy === 'cache-and-network';
 
    if (shouldDispatchClEientResult) {
      this.queryStore.markQueryResultClient(queryId, !shouldFetch);
 
      this.invalidate(true, queryId, fetchMoreForQueryId);
 
      this.broadcastQueries();
    }
 
    if (shouldFetch) {
      const networkResult = this.fetchRequest({
        requestId,
        queryId,
        document: query,
        options,
        fetchMoreForQueryId,
      }).catch(error => {
        // This is for the benefit of `refetch` promises, which currently don't get their errors
        // through the store like watchQuery observers do
        if (isApolloError(error)) {
          throw error;
        } else {
          const { lastRequestId } = this.getQuery(queryId);
          if (requestId >= (lastRequestId || 1)) {
            this.queryStore.markQueryError(queryId, error, fetchMoreForQueryId);
 
            this.invalidate(true, queryId, fetchMoreForQueryId);

            this.broadcastQueries();
          }
 
          this.removeFetchQueryPromise(requestId);
 
          throw new ApolloError({
            networkError: error,
          });
        }
      });
 
      if (fetchPolicy !== 'cache-and-network') {
        return networkResult;
      }
    }
 
    // If we have no query to send to the server, we should return the result
    // found within the store.
    return Promise.resolve<ExecutionResult>({ data: storeResult });
  }
 
  // Returns a query listener that will update the given observer based on the
  // results (or lack thereof) for a particular query.
  public queryListenerForObserver<T>(
    queryId: string,
    options: WatchQueryOptions,
    observer: Observer<ApolloQueryResult<T>>,
  ): QueryListener {
    let previouslyHadError: boolean = false;
    return (queryStoreValue: QueryStoreValue, newData?: DiffResult<T>) => {
      // we're going to take a look at the data, so the query is no longer invalidated
      this.invalidate(false, queryId);
 
      // The query store value can be undefined in the event of a store
      // reset.
      if (!queryStoreValue) return;
 
      //I XXX This is to fix a strange race condition that was the root cause of react-apollo/#170
      // queryStoreValue was sometimes the old queryStoreValue and not what's currently in the store.
      queryStoreValue = this.queryStore.get(queryId);
I
      const { observableQuery } = this.getQuery(queryId);
 
      const fetchPolicy = observableQuery
        ? observableQuery.options.fetchPolicy
        : options.fetchPolicy;
 
      const errorPolicy = observableQuery
        ? observableQuery.options.errorPolicy
        : options.errorPolicy;
 
      // don't watch the store for queries on standby
      if (fetchPolicy === 'standby') return;
 
      const lastResult = observableQuery
        ? observableQuery.getLastResult()
        : null;
 
      const shouldNotifyIfLoading =
        queryStoreValue.previousVariables ||
        fetchPolicy === 'cache-only' ||
        fetchPolicy === 'cache-and-network';
 
      const networkStatusChanged =
        lastResult &&
        queryStoreValue.networkStatus !== lastResult.networkStatus;
 
      if (
        !isNetworkRequestInFlight(queryStoreValue.networkStatus) ||
        (networkStatusChanged && options.notifyOnNetworkStatusChange) ||
        shouldNotifyIfLoading
      ) {
        // If we have either a GraphQL error or a network error, we create
        // an error and tell the observer about it.
        if (
          ((!errorPolicy || errorPolicy === 'none') &&
            queryStoreValue.graphQLErrors &&
            queryStoreValue.graphQLErrors.length > 0) ||
          queryStoreValue.networkError
        ) {
          const apolloError = new ApolloError({
            graphQLErrors: queryStoreValue.graphQLErrors,
            networkError: queryStoreValue.networkError,
          });
          previouslyHadError = true;
          if (observer.error) {
            try {
              observer.error(apolloError);
            } catch (e) {
              // Throw error outside this control flow to avoid breaking Apollo's state
              setTimeout(() => {
                throw e;
              }, 0);
            }
          } else {
            // Throw error outside this control flow to avoid breaking Apollo's state
            setTimeout(() => {
              throw apolloError;
            }, 0);
            if (!isProduction()) {
              /* tslint:disable-next-line */
              console.info(
                'An unhandled error was thrown because no error handler is registered ' +
                  'for the query ' +
                  queryStoreValue.queryString,
              );
            }
          }
        } else {
          try {
            let data: any;
            let isMissing: boolean;
 
            if (newData) {
              // clear out the latest new data, since we're now using it
              this.setQuery(queryId, () => ({ newData: null }));
 
              data = newData.result;
              isMissing = newData.isMissing ? newData.isMissing : false;
            } else {
              if (
                lastResult &&
                lastResult.data &&
                queryStoreValue.previousVariables === queryStoreValue.variables
              ) {
                data = lastResult.data;
        I        isMissing = false;
              } else {
                const { document } = this.getQuery(queryId);
                const readResult = this.dataStore.getCache().diffQuery({
                  query: document as DocumentNode,
                  variables:
                    queryStoreValue.previousVariables ||
                    queryStoreValue.variables,
                  optimistic: true,
                });
 
                data = readResult.result;
                isMissing = readResult.isMissing;
              }
            }
 
            let resultFromStore: ApolloQueryResult<T>;
 
            // If there is some data missing and the user has told us that they
            // do not tolerate partial data then we want to return the previous
            // result and mark it as stale.
            if (isMissing && fetchPolicy !== 'cache-only') {
              resultFromStore = {
                data: lastResult && lastResult.data,
                loading: isNetworkRequestInFlight(
                  queryStoreValue.networkStatus,
                ),
                networkStatus: queryStoreValue.networkStatus,
                stale: true,
              };
            } else {
              resultFromStore = {
                data,
                loading: isNetworkRequestInFlight(
                  queryStoreValue.networkStatus,
                ),
                networkStatus: queryStoreValue.networkStatus,
                stale: false,
              };
            }
 
            // if the query wants updates on errors we need to add it to the result
            if (
              errorPolicy === 'all' &&
              queryStoreValue.graphQLErrors &&
              queryStoreValue.graphQLErrors.length > 0
            ) {
              resultFromStore.errors = queryStoreValue.graphQLErrors;
            }
 
            if (observer.next) {
              const isDifferentResult = !(
                lastResult &&
                resultFromStore &&
                lastResult.networkStatus === resultFromStore.networkStatus &&
                lastResult.stale === resultFromStore.stale &&
                // We can do a strict equality check here because we include a `previousResult`
                // with `readQueryFromStore`. So if the results are the same they will be
                // referentially equal.
                lastResult.data === resultFromStore.data
              );
 
              if (isDifferentResult || previouslyHadError) {
                try {
                  observer.next(maybeDeepFreeze(resultFromStore));
                } catch (e) {
                  // Throw eError outside this control flow to avoid breaking Apollo's state
                  setTimeout(() => {
                    throw e;
                  }, 0);
                }
              }
            }E
            previouslyHadError = false;
          } catch (error) {
            previouslyHadError = true;
            if (observer.error) {
              observer.error(
                new ApolloError({
                  networkError: error,
                }),
              );E
            }
            return;
          }
        }
      }
    };
  }
 
  // The shouldSubscribe option is a temporary fix that tells us whether watchQuery was called
  // directly (i.e. through ApolloClient) or through the query method within QueryManager.
  // Currently, the query method uses watchQuery in order to handle non-network errors correctly
  // but we don't want to keep track observables issued for the query method since those aren't
  // supposed to be refetched in the event of a store reset. Once we unify error handling for
  // network errors and non-network errors, the shouldSubscribe option will go away.
 
  public watchQuery<T>(
    options: WatchQueryOptions,
    shouldSubscribe = true,
  ): ObservableQuery<T> {
    if (options.fetchPolicy === 'standby') {
      throw Inew Error(
        'client.watchQuery cannot be called with fetchPolicy set to "standby"',
      );
    }
 
    // get errors synchronously
    const queryDefinition = getQueryDefinition(options.query);
 
    // assign variable default values if supplied
    if (
      queryDefinition.variableDefinitions &&
      queryDefinition.variableDefinitions.length
    ) {
      const defaultValues = getDefaultValues(queryDefinition);
 
      options.variables = assign({}, defaultValues, options.variables);
    }
 
    if (typeof options.notifyOnNetworkStatusChange === 'undefined') {
      options.notifyOnNetworkStatusChange = false;
    }E
 
    let tranIsformedOptions = { ...options } as WatchQueryOptions;

    return new ObservableQuery<T>({
      scheduler: this.scheduler,
      options: transformedOptions,
      shouldSubscribe: shouldSubscribe,
    });
  }
 
  public query<T>(options: WatchQueryOptions): Promise<ApolloQueryResult<T>> {
    if (!options.query) {
      throw new Error(
        'query option is required. You must specify your GraphQL document in the query option.',
      );
    }
 
    if (options.query.kind !== 'Document') {
      throw new Error('You must wrap the query string in a "gql" tag.');
    }
 
    if ((options as any).returnPartialData) {
      throw new Error('returnPartialData option only supported on watchQuery.');
    }
 
    if ((options as any).pollInterval) {
      throw new Error('pollInterval option only supported on watchQuery.');
    }
 
    if (typeof options.notifyOnNetworkStatusChange !== 'undefined') {
      throw new Error(
        'Cannot call "query" with "notifyOnNetworkStatusChange" option. Only "watchQuery" has that option.',
      );
    }
    options.notifyOnNetworkStatusChange = false;
 
    const requestId = this.idCounter;
    const resPromise = new Promise<ApolloQueryResult<T>>((resolve, reject) => {
      this.addFetchQueryPromise<T>(requestId, resPromise, resolve, reject);
 
      return this.watchQuery<T>(options, false)
        .result()
        .then(result => {
          this.removeFetchQueryPromise(requestId);
          resolve(result);
        })
        .catch(error => {
          this.removeFetchQueryPromise(requestId);
          reject(error);
        });
    });
 
    return resPromise;
  }
 
  public generateQueryId() {
    const queryId = this.idCounter.toString();
    this.idCounter++;
    return queryId;
  }
 
  public stopQueryInStore(queryId: string) {
    this.queryStore.stopQuery(queryId);
    this.invalidate(true, queryId);
    this.broadcastQueries();
  }
 
  public addQueryListener(queryId: string, listener: QueryListener) {
    this.setQuery(queryId, ({ listeners = [] }) => ({
      listeners: [...listeners, listener],
      invalidate: false,
    }));
  }
 
  public updateQueryWatch(queryId: string, options: WatchQueryOptions) {
    let { cancel, document } = this.getQuery(queryId);
    if (cancel) cancel();
 
    cancel = this.dataStore.getCache().watch({
      query: document as DocumentNode,
      variables: options.variables,
      optimistic: true,
      previousResult: () => {
        let previousResult = null;
        const { observableQuery } = this.getQuery(queryId);
        if (observableQuery) {
          const lastResult = observableQuery.getLastResult();
          if (lastResult) {
            previousResult = lastResult.data;
          }
        }
 
        return previousResult;
      },
      callback: (newData: ApolloQueryResult<any>) => {
        this.setQuery(queryId, () => ({ invalidated: true, newData }));
      },
    });
 
    this.setQuery(queryId, () => ({ cancel }));
  }
 
  // Adds a promise to this.fetchQueryPromises for a given request ID.
  public addFetchQueryPromise<T>(
    requestId: number,
    promise: Promise<ApolloQueryResult<T>>,
    resolve: (result: ApolloQueryResult<T>) => void,
    reject: (error: Error) => void,
  ) {
    this.fetchQueryPromises[requestId.toString()] = {
      promise,
      resolve,
      reject,
    };
  }
 
  // Removes the promise in this.fetchQueryPromises for a particular request ID.
  public removeFetchQueryPromise(requestId: number) {
    delete this.fetchQueryPromises[requestId.toString()];
  }
 
  // Adds an ObservableQuery to this.observableQueries and to this.observableQueriesByName.
  public addObservableQuery<T>(
    queryId: string,
    observableQuery: ObservableQuery<T>,
  ) {
    this.setQuery(queryId, () => ({ observableQuery }));
 
    // Insert the ObservableQuery into this.observableQueriesByName if the query has a name
    const queryDef = getQueryDefinition(observableQuery.options.query);
    if (queryDef.name && queryDef.name.value) {
      const queryName = queryDef.name.value;
 
      // XXX we may we want to warn the user about query name conflicts in the future
      this.queryIdsByName[queryName] = this.queryIdsByName[queryName] || [];
      this.queryIdsByName[queryName].push(observableQuery.queryId);
    }
  }
 
  public removeObservableQuery(queryId: string) {
    const { observableQuery } = this.getQuery(queryId);
    if (!observableQuery) return;
 
    const definition = getQueryDefinition(observableQuery.options.query);
    const queryName = definition.name ? definition.name.value : null;
    this.setQuery(queryId, () => ({ observableQuery: null }));
    if (queryName) {
      this.queryIdsByName[queryName] = this.queryIdsByName[
        queryName
      ].filter(val => {
        return !(observableQuery.queryId === val);
      });
    }
  }
 
  public resetStore(): Promise<ApolloQueryResult<any>[]> {
    // Before we have sent the reset action to the store,
    // we can no longer rely on the results returned by in-flight
    // requests since these may depend on values that previously existed
    // in the data portion of the store. So, we cancel the promises and observers
    // that we have issued so far and not yet resolved (in the case of
    // queries).
    Object.keys(this.fetchQueryPromises).forEach(key => {
      const { reject } = this.fetchQueryPromises[key];
      reject(new Error('Store reset while query was in flight.'));
    });
 
    const resetIds: string[] = [];
    this.queries.forEach(({ observableQuery }, queryId) => {
      if (observableQuery) resetIds.push(queryId);
    });
 
    this.queryStore.reset(resetIds);
    this.mutationStore.reset();
    const dataStoreReset = this.dataStore.reset();
 
    // Similarly, we have to have to refetch each of the queries currently being
    // observed. We refetch instead of error'ing on these since the assumption is that
    // resetting the store doesn't eliminate the need for the queries currently being
    // watched. If there is an existing query in flight when the store is reset,
    // the promise for it will be rejected and its results will not be written to the
    // store.
    const observableQueryPromises: Promise<ApolloQueryResult<any>>[] = [];
    this.queries.forEach(({ observableQuery }, queryId) => {
      if (!observableQuery) return;
      const fetchPolicy = observableQuery.options.fetchPolicy;
 
      if (fetchPolicy !== 'cache-only' && fetchPolicy !== 'standby') {
        observableQueryPromises.push(observableQuery.refetch());
      }
 
      this.invalidate(true, queryId);
    });
 
    this.broadcastQueries();
 
    return dataStoreReset.then(() => Promise.all(observableQueryPromises));
  }
 
  public startQuery<T>(
    queryId: string,
    options: WatchQueryOptions,
    listener: QueryListener,
  ) {
    this.addQueryListener(queryId, listener);
 
    this.fetchQuery<T>(queryId, options)
      // `fetchQuery` returns a Promise. In case of a failure it should be caucht or else the
      // console will show an `Uncaught (in promise)` message. Ignore the error for now.
      .catch(() => undefined);
 
    return queryId;
  }
 
  public startGraphQLSubscription(
    options: SubscriptionOptions,
  ): Observable<any> {
    const { query } = options;
    let transformedDoc = this.dataStore.getCache().transformDocument(query);
 
    const variables = assign(
      {},
      getDefaultValues(getOperationDefinition(query)),
      options.variables,
    );
 
    const request: Request = {
      query: transformedDoc,
      variables,
      operationName: getOperationName(transformedDoc) || undefined,
    };
 
    let sub: Subscription;
    let observers: Observer<any>[] = [];
 
    return new Observable(observer => {
      observers.push(observer);
 
      // If this is the first observer, actually initiate the network subscription
      if (observers.length === 1) {
        const handler = {
          next: (result: FetchResult) => {
            this.dataStore.markSubscriptionResult(
              result,
              transformedDoc,
              variables,
            );
            this.broadcastQueries();
 
            // It's slightly awkward that the data for subscriptions doesn't come from the store.
            observers.forEach(obs => {
              if (obs.next) obs.next(result);
            });
          },
          error: (error: Error) => {
            observers.forEach(obs => {
              if (obs.error) obs.error(error);
            });
          },
        };
 
        sub = execute(this.link, request).subscribe(handler);
      }
 
      return () => {
        observers = observers.filter(obs => obs !== observer);
 
        // If we removed the last observer, tear down the network subscription
        if (observers.length === 0 && sub) {
          sub.unsubscribe();
        }
      };
    });
  }
 
  public stopQuery(queryId: string) {
    this.stopQueryInStore(queryId);
    this.removeQuery(queryId);
  }
 
  public removeQuery(queryId: string) {
    this.queries.delete(queryId);
  }
 
  public getCurrentQueryResult<T>(observableQuery: ObservableQuery<T>) {
    const { variables, query } = observableQuery.options;
    const lastResult = observableQuery.getLastResult();
    if (lastResult && lastResult.data) {
      return maybeDeepFreeze({ data: lastResult.data, partial: false });
    } else {
      const { newData } = this.getQuery(observableQuery.queryId);
      if (newData) {
        return maybeDeepFreeze({ data: newData.data, partial: false });
      } else {
        try {
          // the query is brand new, so we read from the store to see if anything is there
          const diffResult = this.dataStore.getCache().read({
            query,
            variables,
            optimistic: true,
          });
 
          return maybeDeepFreeze({ data: diffResult, partial: false });
        } catch (e) {
          return maybeDeepFreeze({ data: {}, partial: true });
        }
      }
    }
  }
 
  public getQueryWithPreviousResult<T>(
    queryIdOrObservable: string | ObservableQuery<T>,
  ) {
    let observableQuery: ObservableQuery<T>;
    if (typeof queryIdOrObservable === 'string') {
      const { observableQuery: foundObserveableQuery } = this.getQuery(
        queryIdOrObservable,
      );
      if (!foundObserveableQuery) {
        throw new Error(
          `ObservableQuery with this id doesn't exist: ${queryIdOrObservable}`,
        );
      }
      observableQuery = foundObserveableQuery;
    } else {
      observableQuery = queryIdOrObservable;
    }
 
    const { variables, query } = observableQuery.options;
 
    const { data } = this.getCurrentQueryResult(observableQuery);
 
    return {
      previousResult: data,
      variables,
      document: query,
    };
  }
 
  public broadcastQueries() {
    this.onBroadcast();
    this.queries.forEach((info, id) => {
      if (!info.invalidated || !info.listeners) return;
      info.listeners
        .filter((x: QueryListener) => !!x)
        .forEach((listener: QueryListener) => {
          // it's possible for the listener to be undefined if the query is being stopped
          // See here for more detail: https://github.com/apollostack/apollo-client/issues/231
          listener(this.queryStore.get(id), info.newData);
        });
    });
  }
 
  // Takes a request id, query id, a query document and information associated with the query
  // and send it to the network interface. Returns
  // a promise for the result associated with that request.
  private fetchRequest<T>({
    requestId,
    queryId,
    document,
    options,
    fetchMoreForQueryId,
  }: {
    requestId: number;
    queryId: string;
    document: DocumentNode;
    options: WatchQueryOptions;
    fetchMoreForQueryId?: string;
  }): Promise<ExecutionResult> {
    const { variables, context, errorPolicy = 'none' } = options;
    const request = {
      query: document,
      variables,
      operationName: getOperationName(document) || undefined,
      context: context || {},
    };
 
    request.context.forceFetch = !this.queryDeduplication;
 
    let resultFromStore: any;
    let errorsFromStore: any;
    const retPromise = new Promise<ApolloQueryResult<T>>((resolve, reject) => {
      this.addFetchQueryPromise<T>(requestId, retPromise, resolve, reject);
      execute(this.deduplicator, request).subscribe({
        next: (result: ExecutionResult) => {
          // default the lastRequestId to 1
          const { lastRequestId } = this.getQuery(queryId);
          if (requestId >= (lastRequestId || 1)) {
            try {
              this.dataStore.markQueryResult(
                result,
                document,
                variables,
                fetchMoreForQueryId,
                errorPolicy === 'ignore',
              );
            } catch (e) {
              reject(e);
              return;
            }
 
            this.queryStore.markQueryResult(
              queryId,
              result,
              fetchMoreForQueryId,
            );
 
            this.invalidate(true, queryId, fetchMoreForQueryId);
 
            this.broadcastQueries();
          }
 
          if (result.errors && errorPolicy === 'none') {
            reject(
              new ApolloError({
                graphQLErrors: result.errors,
              }),
            );
            return;
          } else if (errorPolicy === 'all') {
            errorsFromStore = result.errors;
          }
 
          if (fetchMoreForQueryId) {
            // We don't write fetchMore results to the store because this would overwrite
            // the original result in case an @connection directive is used.
            resultFromStore = result.data;
          } else {
            try {
              // ensure result is combined with data already in store
              resultFromStore = this.dataStore.getCache().read({
                variables,
                query: document,
                optimistic: false,
              });
              // this will throw an error if there are missing fields in
              // the results which can happen with errors from the server.
              // tslint:disable-next-line
            } catch (e) {}
          }
        },
        error: (error: ApolloError) => {
          reject(error);
        },
        complete: () => {
          this.removeFetchQueryPromise(requestId);
          resolve({
            data: resultFromStore,
            errors: errorsFromStore,
            loading: false,
            networkStatus: NetworkStatus.ready,
            stale: false,
          });
        },
      });
    });
 
    return retPromise;
  }
 
  // Refetches a query given that query's name. Refetches
  // all ObservableQuery instances associated with the query name.
  private refetchQueryByName(queryName: string) {
    const refetchedQueries = this.queryIdsByName[queryName];
    // Warn if the query named does not exist (misnamed, or merely not yet fetched)
    if (refetchedQueries === undefined) {
      console.warn(
        `Warning: unknown query with name ${queryName} asked to refetch`,
      );
      return;
    } else {
      return Promise.all(
        refetchedQueries
          .map(id => this.getQuery(id).observableQuery)
          .filter(x => !!x)
          .map((x: ObservableQuery<any>) => x.refetch()),
      );
    }
  }
 
  private generateRequestId() {
    const requestId = this.idCounter;
    this.idCounter++;
    return requestId;
  }
 
  private getQuery(queryId: string) {
    return this.queries.get(queryId) || { ...defaultQueryInfo };
  }
 
  private setQuery(queryId: string, updater: (prev: QueryInfo) => any) {
    const prev = this.getQuery(queryId);
    const newInfo = { ...prev, ...updater(prev) };
    this.queries.set(queryId, newInfo);
  }
 
  private invalidate(
    invalidated: boolean,
    queryId: string,
    fetchMoreForQueryId?: string,
  ) {
    this.setQuery(queryId, () => ({ invalidated }));
 
    if (fetchMoreForQueryId) {
      this.setQuery(fetchMoreForQueryId, () => ({ invalidated }));
    }
  }
}