How create a correct FormData in JavaScript to send content_type: cards?

[AdsonCicilioti]

I have a nodejs application with this function that is responsible for send message data:

private async sendData(
    conversationId: number,
    file: string,
    messageType: 'incoming' | 'outgoing' | undefined,
    content?: string,
    cards?: {
      title?: string;
      description?: string;
      media_url?: string;
    }[],
  ) {
    this.logger.verbose('send data to chatwoot');
    const data = new FormData();

    if (content) {
      this.logger.verbose('content found');
      data.append('content', content);
    }

    if (cards.length > 0) {
      this.logger.verbose('cards found');
      data.append('content_type', 'cards');

      cards.forEach((item, i) => {
        data.append(`content_attributes.items[${i}].title`, item.title);
        data.append(`content_attributes.items[${i}].description`, item.description);
        data.append(`content_attributes.items[${i}].media_url`, item.media_url);
      });
    }

    this.logger.verbose('message type: ' + messageType);
    data.append('message_type', messageType);

    if (file) {
      this.logger.verbose('temp file found');
      data.append('attachments[]', createReadStream(file));
    }

    this.logger.verbose('get client to instance: ' + this.provider.instanceName);
    const config = {
      method: 'post',
      maxBodyLength: Infinity,
      url: `${this.provider.url}/api/v1/accounts/${this.provider.account_id}/conversations/${conversationId}/messages`,
      headers: {
        api_access_token: this.provider.token,
        ...data.getHeaders(),
      },
      data: data,
    };

    this.logger.verbose('send data to chatwoot');
    try {
      const { data } = await axios.request(config);

      if (file) {
        this.logger.verbose('remove temp file');
        unlinkSync(file);
      }

      this.logger.verbose('data sent');
      return data;
    } catch (error) {
      this.logger.error(error);
      if (file) {
        unlinkSync(file);
      }
    }
  }

I'm not sure how to pass card objects to the content_attributes property.

I'm getting the error data: { error: "undefined method 'reject' for nil:NilClass" }