Storage

Storage is a small typed layer over localStorage and sessionStorage. It serializes values with JSON, adds a namespace to keys, and can synchronize a MobX object property with storage.

Example: Save User Settings

import { createStorage } from 'mobx-swiss-knife';

const storage = createStorage({
  prefix: 'app',
  namespace: 'settings',
});

storage.set({ key: 'table', value: { pageSize: 50, compact: true } });

const tableSettings = storage.get({
  key: 'table',
  fallback: { pageSize: 20, compact: false },
});

// Actual key: app/settings/table
console.log(tableSettings);

Synchronizing a Property

class Settings {
  pageSize = 20;

  constructor() {
    const storage = createStorage({ namespace: 'settings' });
    storage.syncProperty(this, 'pageSize', { fallback: 20 });
  }
}

syncProperty first reads the stored value and then writes property changes. The returned disposer disables only this synchronization; destroy() disables all synchronizations for the instance.

Configuration Properties

• prefix, namespace — shared parts of the key.
• type — 'local' or 'session'; defaults to 'local'.
• createKey(params) — completely replace the key-building rules.
• abortSignal — bind the lifecycle to its owner.

Methods

• get({ key, fallback?, prefix?, namespace?, type? }) — return the JSON value or fallback. If the value is missing, the result is null or fallback.
• set({ key, value, format?, prefix?, namespace?, type? }) — store a value. format enables custom serialization.
• syncProperty(context, property, params?) — bind a MobX property to storage and return a disposer.
• destroy() — stop reactions; it does not remove data from storage.

StorageModel and createStorageModel remain as deprecated aliases. Use Storage and createStorage in new code.