Migrating mobx to mobx-state-tree

GithubStore.js

/**
 * mobx store migration to mobx-state-tree system
 **/


// Original MobX Store
import { observable, action, runInAction } from 'mobx';

export default class GithubStore {
  @observable searchName;
  @observable user; // Object with all the user data that comes from the Github API Fetch
  @observable repos; // Array of Repositories that comes from the Github API Fetch
  @observable fetchingData;

  constructor() {
    this.searchName = '';
    this.user = '';
    this.repos = [];
    this.fetchingData = false;
  }

  async fetchFromGithub(endpoint) {
    const url = `https://api.github.com${endpoint}?client_id=my_client_id&client_secret=my_secret_id`;
    const response = await fetch(url);
    return await response.json();
  }

  @action('Change User to search for')
  changeUserToSearchFor(username) {
    this.searchName = username;
  }

  @action('Search for user on Github')
  searchForUser = async () => {
    if (!this.searchName || (this.user && this.searchName === this.user.login))
      return;
    this.fetchingData = true;
    const [user, repos] = await Promise.all([
      this.fetchFromGithub(`/users/${this.searchName}`),
      this.fetchFromGithub(`/users/${this.searchName}/repos`)
    ]);
    runInAction("Update State after fetching Github's Data", () => {
      this.user = user;
      this.repos = repos;
      this.fetchingData = false;
    });
  };
}

// ------------------------------------------------------------------

// mobx-state-tree Store
import { types } from 'mobx-state-tree';

const GithubStore = types.model(
  'GithubStore',
  {
    searchName: types.string,
    user: type.frozen, // Object with all the user data that comes from the Github API Fetch
    repos: type.array, // Array of Repositories that comes from the Github API Fetch
    fetchingData: type.bool
  },
  {
    changeUserToSearchFor(username) {
      this.searchName = username;
    },
    async fetchFromGithub(endpoint) {
      const url = `https://api.github.com${endpoint}?client_id=my_client_id&client_secret=my_secret_id`;
      const response = await fetch(url);
      return await response.json();
    },
    async searchForUser() {
      if (
        !this.searchName || (this.user && this.searchName === this.user.login)
      )
        return;
      this.fetchingData = true;
      const [user, repos] = await Promise.all([
        this.fetchFromGithub(`/users/${this.searchName}`),
        this.fetchFromGithub(`/users/${this.searchName}/repos`)
      ]);
      runInAction("Update State after fetching Github's Data", () => {
        this.user = user;
        this.repos = repos;
        this.fetchingData = false;
      });
    }
  }
);

export default GithubStore;