Optimistic Error Handling Got TypeError Not NetworkError #989

// Back up data to IndexedDB
coordinator.addStrategy(
  new SyncStrategy({
    source: "memory",
    target: "backup",
    blocking: true,
  })
);

// Sync all changes received from the remote server to the memory source
coordinator.addStrategy(
  new SyncStrategy({
    source: "remote",
    target: "memory",
    blocking: true,
  })
);

// Query the remote server whenever the memory source is queried
coordinator.addStrategy(
  new RequestStrategy({
    source: "memory",
    target: "remote",
    on: "beforeQuery",
    action: "query",
    passHints: false,
    blocking: false,
    catch() {
      this.target.requestQueue.skip();
    },
  })
);

// Update the remote server whenever the memory source is updated
coordinator.addStrategy(
  new RequestStrategy({
    source: "memory",
    on: "beforeUpdate",
    target: "remote",
    action: "update",
    passHints: false,
    blocking: false
  })
);

coordinator.addStrategy(
  new RequestStrategy({
    source: "remote",
    on: "updateFail",
    action(transform, e) {
      const source = this.source;
      const store = this.coordinator.getSource("memory");

      // The problem is here, 
      // this if block never gets call when there is network connection problem
      // because the e object is instanceof TypeError and not NetworkError
      if (e instanceof NetworkError) {
        // When network errors are encountered, try again in 3s
        console.log("NetworkError - will try again soon");
        setTimeout(() => {
          source.requestQueue.retry();
        }, 3000);
      } else {
        // When non-network errors occur, notify the user and
        // reset state.
        let label = transform.options && transform.options.label;
        if (label) {
          console.log(`Unable to complete "${label}"`);
        } else {
          console.log(`Unable to complete operation`);
        }

        // Roll back store to position before transform
        if (store.transformLog.contains(transform.id)) {
          console.log("Rolling back - transform:", transform.id);
          store.rollback(transform.id, -1);
        }

        return source.requestQueue.skip();
      }
    }
  })
);

coordinator.addStrategy(
  new RequestStrategy({
    source: "remote",
    on: "queryFail",
    action() {
      this.source.requestQueue.skip();
    },
  })
);