Function tryNext

src/cursor/abstract_cursor.ts:586–617

* Try to get the next available document from the cursor or `null` if an empty batch is returned

()

   * Try to get the next available document from the cursor or `null` if an empty batch is returned
   */
  async tryNext(): Promise<TSchema | null> {
    this.signal?.throwIfAborted();

    if (this.cursorId === Long.ZERO) {
      throw new MongoCursorExhaustedError();
    }

    if (this.cursorOptions.timeoutMode === CursorTimeoutMode.ITERATION && this.cursorId != null) {
      this.timeoutContext?.refresh();
    }
    try {
      let doc = this.documents?.shift(this.deserializationOptions);
      if (doc != null) {
        if (this.transform != null) return await this.transformDocument(doc);
        return doc;
      }

      await this.fetchBatch();

      doc = this.documents?.shift(this.deserializationOptions);
      if (doc != null) {
        if (this.transform != null) return await this.transformDocument(doc);
        return doc;
      }
    } finally {
      if (this.cursorOptions.timeoutMode === CursorTimeoutMode.ITERATION) {
        this.timeoutContext?.clear();
      }
    }

    return null;
  }

  /**
   * Iterates over all the documents for this cursor using the iterator, callback pattern.