Persistence

To survive hard refreshes from the user, your state can be persisted to sessionStorage automatically.
This will re-hydrate your store on initialisation.

// An initialised store. Params omitted for brevity
const store = createAppState('an.example.store', {
  persist: 'food' // this must be a unique namespace for the store
})

createPersist function

You can optionally save state to window.localStorage (for persistence across browser sessions) using the createPersist function:

import { createAppState, createPersist } from 'https://cdn.skypack.dev/ficusjs@6'

// An initialised store. Params omitted for brevity
const store = createAppState('an.example.store', {
  persist: createPersist('food', 'local')
})

When using the createPersist function, the following arguments must be supplied:

Options

Options can be provided when creating persistence.

import { createAppState, createPersist } from 'https://cdn.skypack.dev/ficusjs@6'

// An initialised store. Params omitted for brevity
const store = createAppState('an.example.store', {
  initialState: {
    count: 0,
    currentRun: 0
  },
  persist: createPersist('food', 'local', {
    clearOnReload: true,
    saveState (state) {
      return {
        count: state.count
      }
    }
  })
})

options.clearOnReload

Setting options.clearOnReload to true will detect the browser reload state using
the window.performance API and clear the persistence
if a reload type is detected.

createPersist('food', 'local', {
  clearOnReload: true
})

options.saveState

Setting options.saveState provides a way to persist specific data different to that of the store state.
This is useful when the store state contains functions or other data that cannot be serialised into a string when saved
to window.sessionStorage or window.localStorage.

createPersist('food', 'local', {
  saveState (state) {
    return {
      // return properties of state to persist
    }
  }
})

The saveState function is passed the current state and must return an object of data to be serialised into a string.

Custom persistence

You can provide a custom class and persist your application state in whichever way you choose.

Four methods must be implemented:

import { createAppState } from 'https://cdn.skypack.dev/ficusjs@6'

class MyCustomPersist {
  setState (state) {
    // set the state
  }

  getState () {
    // get the state
  }

  lastUpdated () {
    // get the last updated time in milliseconds since the Unix Epoch
  }

  removeState () {
    // remove the state - this is called by default when setState is null
  }
}

// An initialised store. Params omitted for brevity
const store = createAppState('an.example.store', {
  persist: new MyCustomPersist()
})