How to save Mobx state in sessionStorage

Question

Trying to essentially accomplish this https://github.com/elgerlambert/redux-localstorage which is for Redux but do it for Mobx. And preferably would like to use sessionStorage. Is there an easy way to accomplish this with minimal boilerplate?

Answer 1

The easiest way to approach this would be to have a mobx "autorun" triggered whenever any observable property changes. To do that, you could follow my answer to this question.

I'll put some sample code here that should help you get started:

function autoSave(store, save) {
  let firstRun = true;
  mobx.autorun(() => {
    // This code will run every time any observable property
    // on the store is updated.
    const json = JSON.stringify(mobx.toJS(store));
    if (!firstRun) {
      save(json);
    }
    firstRun = false;
  });
}

class MyStore {
  @mobx.observable prop1 = 999;
  @mobx.observable prop2 = [100, 200];

  constructor() {
    this.load();
    autoSave(this, this.save.bind(this));
  }

  load() {
    if (/* there is data in sessionStorage */) {
      const data = /* somehow get the data from sessionStorage or anywhere else */;
      mobx.extendObservable(this, data);
    }
  }

  save(json) {
    // Now you can do whatever you want with `json`.
    // e.g. save it to session storage.
    alert(json);
  }
}