api.js

export var getAPI = (endpoint, data = {}, opts = {}) => {
  let url = makeUrl(endpoint, opts);
  let request = superagent.get(url).query(data);
  let promise = makePromise(request);

  return promise;
};

var makePromise = (request) => {
  return new Promise(function(resolve, reject) {
      request
      .set('Accept', 'application/json')
      .set('X-CSRF-Token', csrfToken)
      .type('json')
      .timeout(TIMEOUT)
      .end(function(err, res) {
        if (typeof res != 'undefined' && res.status === 401) {
          reject(new UnauthorizedRequestError());
        } else if (typeof res != 'undefined' && res.status >= 400) {
          let msg = `Failed to ${request.method} ${request.url} (${res.status})`;
          let error = new SuperagentRequestError(msg);
          error.status = res.status;
          error.body = res.body;
          error.res = res;

          reject(error);
        } else if (err) {
          reject(new SuperagentGeneralError(err));
        } else {
          resolve(res);
        }
      });
    })
    .catch((err) => {
      console.log('Honeybadger report.');
      throw err;
    })
    .catch(UnauthorizedRequestError, function(e) {
      sessionExpiredRedirect();
    });
};

function UnauthorizedRequestError(message) {}
UnauthorizedRequestError.prototype = Object.create(Error.prototype);

function SuperagentGeneralError(message) {
  this.name = 'SuperagentGeneralError';
  this.message = message || 'General error';
  this.timestamp = new Date();
  Error.captureStackTrace(this, SuperagentGeneralError);
}
SuperagentGeneralError.prototype = Object.create(Error.prototype);
SuperagentGeneralError.prototype.constructor = SuperagentGeneralError;

function SuperagentRequestError(message) {
  this.name = 'SuperagentRequestError';
  this.message = message || 'Bad request';
  this.timestamp = new Date();
}
SuperagentRequestError.prototype = Object.create(Error.prototype);
SuperagentRequestError.prototype.constructor = SuperagentRequestError;