# recoil-sync-next

[![npm version](https://badge.fury.io/js/recoil-sync-next.svg)](https://badge.fury.io/js/recoil-sync-next)

[Recoil Sync](https://recoiljs.org/docs/recoil-sync/introduction) stores for Next.js

## Caution

**The new router for the `app/` directory introduced by Next.js 13 is not yet supported.**

## Features

- [URL Persistence](#url-persistence)
  - Syncing an atom with the browser URL.
- [Session Storage Persistence Synced with History](#session-storage-persistence-synced-with-history)
  - Syncing an atom with the history position.
- [Utilities](#utilities)

## Installation

```shell
npm install recoil recoil-sync recoil-sync-next
# or
yarn add recoil recoil-sync recoil-sync-next
# or
pnpm add recoil recoil-sync recoil-sync-next
```

## URL Persistence

This provides recoil-sync's [URL Persistence](https://recoiljs.org/docs/recoil-sync/url-persistence)
functionality interfaced with [next/router](https://nextjs.org/docs/api-reference/next/router).

### Notes

`<RecoilURLSyncJSON>` and `<RecoilURLSyncTransit>` always use
[shallow routing](https://nextjs.org/docs/routing/shallow-routing)
to update the browser URL.
When the URL has changed, they cause re-rendering of themselves.
Therefore, you should concider to use `React.memo()`
for Page components that use URL synced atoms (
[example](https://github.com/recruit-tech/recoil-sync-next/blob/main/examples/react-hook-form/pages/url-form/[index].tsx)
).

### \<RecoilURLSyncJSONNext>

A version of [\<RecoilURLSyncJSON>](https://recoiljs.org/docs/recoil-sync/api/RecoilURLSyncJSON) that works with next/router
to sync atoms with the browser URL using JSON encoding.
This should be a child element of [\<RecoilRoot>](https://recoiljs.org/docs/api-reference/core/RecoilRoot).

```typescript
function RecoilURLSyncJSONNext(props: {
  storeKey?: string | undefined
  location: LocationOption
  children: ReactNode
}): ReactNode
```

#### Props

- `storeKey`
  - This prop is used to match up which atoms should sync with this external store.
    See [Syncing with Multiple Storages](https://recoiljs.org/docs/recoil-sync/sync-effect#syncing-with-multiple-storages) for more info.
- `location`
  - Tis prop specifies what part of the URL to sync.
    See [URL Location](https://recoiljs.org/docs/recoil-sync/api/RecoilURLSync#url-location) for more info.
- `children`
  - React elements in your component tree.

#### Example

```tsx
import { RecoilURLSyncJSONNext } from 'recoil-sync-next'

function MyApp({ Component, pageProps }: AppProps) {
  return (
    <RecoilRoot>
      <RecoilURLSyncJSONNext location={{ part: 'queryParams' }}>
        <Component {...pageProps} />
      </RecoilURLSyncJSONNext>
    </RecoilRoot>
  )
}
```

### \<RecoilURLSyncTransitNext>

A version of [\<RecoilURLSyncTransit>](https://recoiljs.org/docs/recoil-sync/api/RecoilURLSyncTransit) that works with next/router
to sync atoms with the browser URL using [Transit encoding](https://github.com/cognitect/transit-js).
This should be a child element of [\<RecoilRoot>](https://recoiljs.org/docs/api-reference/core/RecoilRoot).

```typescript
function RecoilURLSyncTransitNext(props: {
  storeKey?: string | undefined
  location: LocationOption
  handlers?: ReadonlyArray<TransitHandler<any, any>>
  children: ReactNode
}): ReactNode
```

#### Props

- `storeKey`
  - This prop is used to match up which atoms should sync with this external store.
    See [Syncing with Multiple Storages](https://recoiljs.org/docs/recoil-sync/sync-effect#syncing-with-multiple-storages) for more info.
- `location`
  - Tis prop specifies what part of the URL to sync.
    See [URL Location](https://recoiljs.org/docs/recoil-sync/api/RecoilURLSync#url-location) for more info.
- `handlers`
  - The array of user defined custom encoder/decoder object.
    See [Custom Classes](https://recoiljs.org/docs/recoil-sync/api/RecoilURLSyncTransit#custom-classes) for more info.
- `children`
  - React elements in your component tree.

#### Example

```tsx
import { RecoilURLSyncTransitNext } from 'recoil-sync-next'

function MyApp({ Component, pageProps }: AppProps) {
  return (
    <RecoilRoot>
      <RecoilURLSyncTransitNext location={{ part: 'queryParams' }}>
        <Component {...pageProps} />
      </RecoilURLSyncTransitNext>
    </RecoilRoot>
  )
}
```

### \<RecoilURLSyncNext>

A version of [\<RecoilURLSync>](https://recoiljs.org/docs/recoil-sync/api/RecoilURLSync) that works with next/router
to sync atoms with the browser URL using your own serialize/deserialize algorithms.
This should be a child element of [\<RecoilRoot>](https://recoiljs.org/docs/api-reference/core/RecoilRoot).

```typescript
function RecoilURLSyncNext(props: {
  storeKey?: string | undefined
  location: LocationOption
  serialize: (data: unknown) => string
  deserialize: (str: string) => unknown
  children: ReactNode
}): ReactNode
```

#### Props

- `storeKey`
  - This prop is used to match up which atoms should sync with this external store.
    See [Syncing with Multiple Storages](https://recoiljs.org/docs/recoil-sync/sync-effect#syncing-with-multiple-storages) for more info.
- `location`
  - This prop specifies what part of the URL to sync.
    See [URL Location](https://recoiljs.org/docs/recoil-sync/api/RecoilURLSync#url-location) for more info.
- `serialize`
  - The callback can provide custom serializations.
    See [Custom serialization](https://recoiljs.org/docs/recoil-sync/api/RecoilURLSync#custom-serialization) for more info.
- `deserialize`
  - The callback can provide custom deserializations.
    See [Custom serialization](https://recoiljs.org/docs/recoil-sync/api/RecoilURLSync#custom-serialization) for more info.
- `children`
  - React elements in your component tree.

#### Example

```tsx
import { RecoilURLSyncNext } from 'recoil-sync-next'
import qs from 'qs'

function MyApp({ Component, pageProps }: AppProps) {
  return (
    <RecoilRoot>
      <RecoilURLSyncNext
        location={{ part: 'queryParams' }}
        serialize={qs.stringify}
        deserialize={qs.parse}
      >
        <Component {...pageProps} />
      </RecoilURLSyncNext>
    </RecoilRoot>
  )
}
```

## Session Storage Persistence Synced with History

Provides persistence of atoms to session storage synced with the position of the history entry.
It will save atoms to session storage when the history entry's position is moved.
When the user moves backward/forward on history entries (i.e. `'popstate'` event is fired),
the atoms saved with that position is restored.

#### \<RecoilHistorySyncJSONNext>

To sync atoms with the position of the history entry using JSON encoding.
This should be a child element of [\<RecoilRoot>](https://recoiljs.org/docs/api-reference/core/RecoilRoot).

```typescript
function RecoilHistorySyncJSONNext(props: {
  storeKey?: string | undefined
  children: ReactNode
}): ReactNode
```

#### Props

- `storeKey`
  - This prop is used to match up which atoms should sync with this external store.
    See [Syncing with Multiple Storages](https://recoiljs.org/docs/recoil-sync/sync-effect#syncing-with-multiple-storages) for more info.
- `children`
  - React elements in your component tree.

#### Example

```tsx
import { RecoilHistorySyncJSONNext } from 'recoil-sync-next'

function MyApp({ Component, pageProps }: AppProps) {
  return (
    <RecoilRoot>
      <RecoilHistorySyncJSONNext>
        <Component {...pageProps} />
      </RecoilHistorySyncJSONNext>
    </RecoilRoot>
  )
}
```

### \<RecoilHistorySyncTransitNext>

To sync atoms with the position of the history entry using [Transit encoding](https://github.com/cognitect/transit-js).
This should be a child element of [\<RecoilRoot>](https://recoiljs.org/docs/api-reference/core/RecoilRoot).

```typescript
function RecoilHistorySyncTransitNext(props: {
  storeKey?: string | undefined
  handlers?: ReadonlyArray<TransitHandler<any, any>>
  children: ReactNode
}): ReactNode
```

#### Props

- `storeKey`
  - This prop is used to match up which atoms should sync with this external store.
    See [Syncing with Multiple Storages](https://recoiljs.org/docs/recoil-sync/sync-effect#syncing-with-multiple-storages) for more info.
- `handlers`
  - The array of user defined custom encoder/decoder object.
    See [Custom Classes](https://recoiljs.org/docs/recoil-sync/api/RecoilURLSyncTransit#custom-classes) for more info.
- `children`
  - React elements in your component tree.

#### Example

```tsx
import { RecoilHistorySyncTransitNext } from 'recoil-sync-next'

function MyApp({ Component, pageProps }: AppProps) {
  return (
    <RecoilRoot>
      <RecoilHistorySyncTransitNext>
        <Component {...pageProps} />
      </RecoilHistorySyncTransitNext>
    </RecoilRoot>
  )
}
```

## Utilities

### initializableAtom

`atom`, but initial value can be specified when using it.

Note: This is just a utility and does not depend on either Recoil Sync or Next.js.

```typescript
function initializableAtom<T extends SerializableParam>(options: {
  key: string
  effects?:
    | ReadonlyArray<AtomEffect<T>>
    | ((param: P) => ReadonlyArray<AtomEffect<T>>)
  dangerouslyAllowMutability?: boolean
}): (initialValue: T) => RecoilState<T>
```

#### Type Parameters

- T
  - The type of the atom value.
    It must be compared using value-equality and must be serializable.

#### Parameters

See [atom](https://recoiljs.org/docs/api-reference/core/atom) for more info.

#### Return

A function which takes its `initialValue`.

#### Example

```tsx
import { initializableAtom } from 'recoil-sync-next'

const countState = initializableAtom<number>({
  key: 'count',
})

const MyComponent: React.FC = () => {
  const [count, setCount] = useRecoilState(countState(100)) // count is initialized to 100
  ...
}
```

### initializableAtomFamily

`atomFamily`, but initial value can be specified individually when using it.

Note: This is just a utility and does not depend on either Recoil Sync or Next.js.

```typescript
function initializableAtomFamily<
  T extends SerializableParam,
  P extends SerializableParam
>(options: {
  key: string
  effects?:
    | ReadonlyArray<AtomEffect<T>>
    | ((param: P) => ReadonlyArray<AtomEffect<T>>)
  dangerouslyAllowMutability?: boolean
}): (parameter: P, initialValue: T) => RecoilState<T>
```

#### Type Parameters

- T
  - The type of the atom value.
    It must be compared using value-equality and must be serializable.
- P
  - The type of the paramter that map to each atom.
    It must be compared using value-equality and must be serializable.

#### Parameters

See [atomFamily](https://recoiljs.org/docs/api-reference/utils/atomFamily) for more info.

#### Return

A function which takes `parameter` that map to an atom, and its `initialValue`.

#### Example

```tsx
import { initializableAtomFamily } from 'recoil-sync-next'

const countState = initializableAtomFamily<number, string>({
  key: 'count',
})

const MyComponent: React.FC = () => {
  const [count1, setCount1] = useRecoilState(countState('foo', 0))   // count1 is initialized to 0
  const [count2, setCount2] = useRecoilState(countState('bar', 100)) // count2 is initialized to 100
  ...
}
```