Method next

src/change_stream.ts:747–779

Get the next available document from the Change Stream.

()

  /** Get the next available document from the Change Stream. */
  async next(): Promise<TChange> {
    this._setIsIterator();
    // Change streams must resume indefinitely while each resume event succeeds.
    // This loop continues until either a change event is received or until a resume attempt
    // fails.
    this.timeoutContext?.refresh();

    try {
      while (true) {
        try {
          const change = await this.cursor.next();
          const processedChange = this._processChange(change ?? null);
          return processedChange;
        } catch (error) {
          try {
            await this._processErrorIteratorMode(error, this.cursor.id != null);
          } catch (error) {
            if (error instanceof MongoOperationTimeoutError && this.cursor.id == null) {
              throw error;
            }
            try {
              await this.close();
            } catch (error) {
              squashError(error);
            }
            throw error;
          }
        }
      }
    } finally {
      this.timeoutContext?.clear();
    }
  }

  /**
   * Try to get the next available document from the Change Stream's cursor or `null` if an empty batch is returned