WitService.ts

import HttpService from './HttpService';

export default class WitService {
  constructor(private readonly httpService: HttpService) {
    ['WIT_API_URL', 'WIP_API_TOKEN'].forEach((environmentVar) => {
      if (!process.env[environmentVar]) {
        throw new Error(`Missing ${environmentVar} environment var`);
      }
    });
  }

  public async getTextFromSpeech(
    content: string,
    type: 'audio/wav' | 'audio/mpeg3' | 'audio/ogg' | 'audio/ulaw' | 'audio/raw'
  ): Promise<string> {
    const response = await this.httpService.post(
      `${process.env.WIT_API_URL}/speech`,
      Buffer.from(content, 'base64'),
      {
        params: {
          v: '20200513',
        },
        headers: {
          Authorization: `Bearer ${process.env.WIP_API_TOKEN}`,
          'Content-Type': type,
        },
      }
    );

    return response.data.text;
  }
}