Download a Google Drive file of a given type with a JSON Web Token via Drive Api v3

index.js

/**
 * Simple Node Script for Downloading Google Drive files (Drive API v3).
 * Use these instructions to get a GAPI_CLIENT_EMAIL and GAPI_PRIVATE_KEY: https://github.com/The-Politico/api-to-sheets#making-a-google-service-account
 * See all available types by document here: https://developers.google.com/drive/api/v3/manage-downloads
 */

const { JWT } = require('google-auth-library');
const { google } = require('googleapis');

const client = new JWT({
  email: GAPI_CLIENT_EMAIL,
  key: GAPI_PRIVATE_KEY,
  scopes: ['https://www.googleapis.com/auth/drive'],
});

const getData = (fileId, mimeType = 'text/plain') => {
  const drive = google.drive('v3');
  return new Promise((resolve, reject) => {
    drive.files.export({
      auth: client,
      fileId,
      mimeType,
    }, (err, resp) => {
      if (err) { reject(err); };
      resolve(resp.data);
    });
  });
};

client.authorize()
  .then(() => getData(FILE_ID, FILE_TYPE))
  .then(d => { console.log(d); }) // Do something with the file
  .catch(err => { console.log(err); });