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fluxible-immutable-store

Fluxible Immutable Store

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A helper function to create stores that protect private data from being set from outside. That is the one and only feature of this module.

Use whatever data structures you want inside. You can choose to use immutable data structures from Immutable, Mori, or any other library, or you can choose to return deep clones of your internal data. All this function does is help you keep the internals of your store internal.

The library relies on Yahoo!'s Dispatchr createStore function. You can use these stores with just the dispatcher or with Yahoo!'s Fluxible library.

Installation

npm install --save fluxible-immutable-store

Example

Here is part of a reimplementation of the TodoStore from the Fluxible examples. It uses Facebook's Immutable data structures internally, but that is merely a design choice, not a requirement of this module.

var Immutable = require('immutable');
var createImmutableStore = require('fluxible-immutable-store');
 
var TodoStore = createImmutableStore(function () {
  // Hide any data you want in variables declared in the closure 
  var todos;
 
  // This is the spec that is expected by createStore 
  return {
    storeName: 'TodoStore',
    handlers: {
      'CREATE_TODO_START': '_createTodoStart'
    },
    initialize: function () {
      todos = Immutable.List();
    },
    _createTodoStart: function (todo) {
      todos = todos.push(Immutable.Map(todo));
      this.emitChange();
    },
 
    // Define the accessors to the internal state 
    accessors: {
      'todos': function () {
        return todos.toJS();
      }
    }
  };
});
 
module.exports = TodoStore;

The variables that represent the store's state can be exposed as accessors. They will have read-only properties created for them. If you use an immutable data structure, then there will be no way to set the property from the outside or to mutate the structure's internal data.

In your component that needs access to the TodoStore, you would have code similar to this:

var TodoList = React.createClass({
  mixins: [ StoreMixin ],
 
  statics: {
    storeListeners: [ 'TodoStore' ]
  },
 
  // Called when TodoStore emits a change event 
  onChange: function onChange() {
    var todoStore = this.getStore('TodoStore');
    this.setState({
      todos: todoStore.todos
    });
  }
 
  render: function render() {
    ...
  }
});

You won't be able to reassign a new object to the todoStore.todos field, thus getting you one step closer to an immutable store.

Alternate Accessor Definition

Alternatively, you can set the private data on the privates object that is passed into your spec factory function and define the accessors as a simple array of field names. If you do not need to change the data structure upon access (such as converting an Immutable.List to a plain Javascript array), then this method is more succinct.

var Immutable = require('immutable');
var createImmutableStore = require('fluxible-immutable-store');
 
// Set any private field data as fields on `privates` 
var TodoStore = createImmutableStore(function (privates) {
  // This is the spec that is expected by createStore 
  return {
    storeName: 'TodoStore',
    handlers: {
      'CREATE_TODO_START': '_createTodoStart'
    },
    initialize: function () {
      privates.todos = Immutable.List();
    },
    _createTodoStart: function (todo) {
      privates.todos = privates.todos.push(Immutable.Map(todo));
      this.emitChange();
    },
 
    // Define the accessors to the internal state by their names in `privates` 
    accessors: [ 'todos' ]
  };
});
 
module.exports = TodoStore;