SessionStore.js

import { action, observable } from 'mobx';

export class SessionStore {
  constructor() {}

  @observable accessToken = null;
  @observable user = null;
  @observable isLoading = false;

  async logInByAccessToken(accessToken) {
    this._setLoading(true);
    await this._setAccessToken(accessToken);
    await this._fetchUser();
    this._setLoading(false);
  }

  async logInWithFacebookAccessToken(facebookAccessToken) {
    this._setLoading(true);
    const response = await axios.get(SMUGL_API_FACEBOOK_TOKEN_CALLBACK, {
      params: {
        access_token: facebookAccessToken
      }
    });

    await this._setAccessToken(response.data.content.token);
    await this._fetchUser();
    this._setLoading(false);
  }

  @action
  _setLoading(isLoading) {
    this.isLoading = isLoading;
  }

  // ...
}