Discord Channel Transcript using REST API (NestJS)

discord-transcript.ts

async fetchMessages(channelId: string): Promise<string[]> {
    let messages = [];
    let beforeMessageId = '';
    while (beforeMessageId !== null) {
      const { data } = await this.httpService
        .get(
          `${API_URL}/channels/${channelId}/messages?limit=100${
            beforeMessageId ? `&before=${beforeMessageId}` : ''
          }`,
          {
            headers: {
              authorization: this.discordBotAuthorization,
            },
          },
        )
        .toPromise();

      data.reverse();
      beforeMessageId = data.length && data.length === 100 ? data[0].id : null;
      messages = [
        ...data.map(d => {
          return `[${DateTime.fromISO(d.timestamp).toFormat(
            'MM-dd-yyyy HH:mm',
          )}] ${d.author.username}#${d.author.discriminator} <${
            d.author.id
          }>: ${d.content}`;
        }),
        ...messages,
      ];
    }
    return messages;
  }