Add adapter key prefix

[yumauri]

Let's say you have two separate applications on the same domain

• https://domain/app1/
• https://domain/app2/

As long as they are located on the same domain — they shares same local storage space. And this can lead to keys conflicts. For example, both applications has store $isAuthenticated and both applications persists this store with the key authenticated in storage.

It could be hard to maintain unique keys manually, so, idea is to add possibility to specify global (per adapter) key prefix. For example:

import { createStore } from 'effector'
import { persist, configure } from 'effector-storage/local'

configure({
  keyPrefix: 'app1/'
})

const $isAuthenticated = createStore(false)
persist({
  store: $isAuthenticated,
  key: 'authenticated' // <- actual localStorage key will be "app1/authenticated"
})

(This API example is just an idea and subject to change)

[AlexandrHoroshih]

The global configuration tricks look very suspicious to me

Maybe something like this?

const appPersist = createPersist({
 prefix: 'app1/',
 //  more configuration options can be added in the future, if needed
})

const $isAuthenticated = createStore(false)
appPersist({
  store: $isAuthenticated,
  key: 'authenticated' // <- actual localStorage key will be "app1/authenticated"
})

// this way we can also persist a value, that is shared for both apps, if we need this
persist({
 store: $shared,
 key: 'shared-value'
})

[yumauri]

Hm, I agree, this looks more robust.

But it is always irritates me in ky that if I want to change some options globally — I need to create separate instance of ky and use it everywhere across the application...

What about both ways?
For example axios supports changing global defaults and creating separate instance with its own defaults:
https://github.com/axios/axios#config-defaults

[yumauri]

Taking axios behaviour as an example:

Global configuration:

persist.defaults.keyPrefix = 'app/'

const $isAuthenticated = createStore(false)
persist({
  store: $isAuthenticated,
  key: 'authenticated' // <- actual localStorage key will be "app/authenticated"
})

Instance configuration:

const appPersist = persist.create({
  keyPrefix: 'app/',
})

const $isAuthenticated = createStore(false)
appPersist({
  store: $isAuthenticated,
  key: 'authenticated' // <- actual localStorage key will be "app/authenticated"
})

// defaults can be changed on instance as well
appPersist.defaults.keyPrefix = 'app2/'

[AlexandrHoroshih]

I don't know, i really don't like global configration hooks
🤷

What is correct behavior, if user changed global configuration long after all persists are set? or if global configuration changes on the fly?

Maybe forbid to change configuration if there are persisted stores already, or allow to call this configure function only one time? 🤔

[yumauri]

After several days of thinking I have come to conclusion, that you are right — global configuration will add useless complexity and strange behaviour.

Added createPersist factory in version 4.4.0.