ImmutableStore

Tiny observable wrapper around Immutable JS with rewind/replay support. Use normal Immutable JS methods to update the store. Subscribe to be notified of changes.

Installation

npm install immutable-js-store

Api

constructor(initialState: ?Object)

Initialize the store (with an optional default state).

clearHistory(): Immutable.Collection

Removes all history before the current cursor.

getState(): Immutable.Collection

Returns the reference to the Immutable state at the current cursor. By default the cursor will point to the most recent state. Use the "step" methods to modify the cursor and undo or replay events.

hasNext(): boolean

Is there a newer state (after) the current cursor?

hasPrevious(): boolean

Is there an older state (before) the current cursor?

jumpToEnd(): ?Immutable.Collection

Move the cursor to the most recent (last) state. This will notify all current subscribers. This method returns the value of the state at the updated cursor if the cursor has changed.

jumpToStart(): ?Immutable.Collection

Move the cursor to the very first (initial) state. This will notify all current subscribers. This method returns the value of the state at the updated cursor if the cursor has changed.

stepBack(): ?Immutable.Collection

Decrease the cursor by 1, to the state that came before the current one. This will notify all current subscribers. This method returns the value of the state at the updated cursor if the cursor has changed.

stepForward(): ?Immutable.Collection

Increase the cursor by 1, to the state that came after the current one. This will notify all current subscribers. This method returns the value of the state at the updated cursor if the cursor has changed.

subscribe(subscriber): Function

Subscribe to store changes. Subscribers will be passed a reference to the current store-state when updates are made. Stepping backwards or forward will notify subscribers of the updated "current" state. This method returns an unsubscribe function; invoke it to stop being notified of changes to the store.

subscribeIn(path, subscriber): Function

Memoized subscription to a specific path in the Immutable store. Subscribers will be passed the value contained at the specified path within the current store-state. This method returns an unsubscribe function; invoke it to stop being notified of changes to the store.

Example

import ImmutableStore from 'immutable-js-store'

// Simple example store with a default state
const store = new ImmutableStore({
  user: {
    id: 1,
    name: 'Brian'
  },
  counter: 0
})

// Subscribe to any top-level store changes
const unsubscribeFromStore = store.subscribe(
  (store) => console.log(JSON.stringify(store.toJS()))
)

// Subscribe only to changes below store.user.name
const unsubscribeFromName = store.subscribeIn(['user', 'name'],
  (name) => console.log('name:', name)
)

store.set('counter', store.get('counter') + 1)
// { user: { id: 1, name: 'Brian' }, counter: 1}

store.set('counter', store.get('counter') + 1)
// { user: { id: 1, name: 'Brian' }, counter: 2}

store.setIn(['user', 'name'], 'Brian Vaughn')
// { user: { id: 1, name: 'Brian Vaughn' }, counter: 2}
// name: Brian Vaughn

store.stepBack()
// { user: { id: 1, name: 'Brian' }, counter: 2}
// name: Brian

store.stepBack()
// { user: { id: 1, name: 'Brian' }, counter: 1}

store.stepForward()
// { user: { id: 1, name: 'Brian' }, counter: 2}

store.stepForward()
// { user: { id: 1, name: 'Brian Vaughn' }, counter: 2}
// name: Brian Vaughn