Ember Array that writes every change to localStorage

local-storage-array.js

export default Ember.ArrayProxy.extend({
  localStorageKey: null,

  init: function() {
    var localStorageKey = this.get('localStorageKey');

    if (!localStorageKey) {
      throw new Error("You must specify which property name should be used to save " + this + " in localStorage by setting its localStorageKey property.");
    }

    // Retrieve the serialized version from localStorage using the specified
    // key.
    var serialized = localStorage[localStorageKey];
    var content;

    // If there is a serialized array available, deserialize it and use it
    // as the underlying array. Otherwise, create a new empty array.
    if (serialized) {
      content = JSON.parse(serialized);
    } else {
      content = [];
    }

    this.set('content', content);

    return this._super.apply(this, arguments);
  },

  replaceContent: function(idx, amount, objects) {
    this._super(idx, amount, objects);
    this.save();
  },

  save: function() {
    var content = this.get('content');
    var localStorageKey = this.get('localStorageKey');

    localStorage[localStorageKey] = JSON.stringify(content);
  }
});

Great work. I took the idea and made an ember-cli addon: https://github.com/funkensturm/ember-local-storage