refactor(store) simplify key value store, add SWR through local stora…

…ge behavior (#7554)

packages/sanity/src/core/store/key-value/index.ts

@@ -1,2 +1,2 @@
-export * from './KeyValueStore'
+export * from './keyValueStore'
 export * from './types'

packages/sanity/src/core/store/key-value/keyValueStore.ts

@@ -0,0 +1,9 @@
+import {type SanityClient} from '@sanity/client'
+
+import {withLocalStorageSWR} from './localStorageSWR'
+import {createServerKeyValueStore} from './serverKeyValueStore'
+
+/** @internal */
+export function createKeyValueStore(options: {client: SanityClient}) {
+  return withLocalStorageSWR(createServerKeyValueStore(options))
+}

packages/sanity/src/core/store/key-value/localStorageSWR.ts

@@ -0,0 +1,39 @@
+import {isEqual} from 'lodash'
+import {fromEvent, merge, NEVER} from 'rxjs'
+import {distinctUntilChanged, filter, map, tap} from 'rxjs/operators'
+
+import {localStoreStorage} from './storage/localStoreStorage'
+import {type KeyValueStore, type KeyValueStoreValue} from './types'
+
+// Whether or not to enable instant user sync between tabs
+// if set to true, the setting will update instantly across all tabs
+const ENABLE_CROSS_TAB_SYNC = false
+
+/**
+ * Wraps a KeyValueStore and adds Stale-While-Revalidate (SWR) behavior to it
+ */
+export function withLocalStorageSWR(wrappedStore: KeyValueStore): KeyValueStore {
+  const storageEvent = ENABLE_CROSS_TAB_SYNC ? fromEvent<StorageEvent>(window, 'storage') : NEVER
+
+  function getKey(key: string) {
+    const lsUpdates = storageEvent.pipe(
+      filter((event) => event.key === key),
+      map(() => localStoreStorage.getKey(key)),
+    )
+
+    return merge(lsUpdates, wrappedStore.getKey(key)).pipe(
+      distinctUntilChanged(isEqual),
+      tap((value) => {
+        localStoreStorage.setKey(key, value)
+      }),
+    )
+  }
+  function setKey(key: string, nextValue: KeyValueStoreValue) {
+    localStoreStorage.setKey(key, nextValue)
+    return wrappedStore.setKey(key, nextValue)
+  }
+  return {
+    getKey,
+    setKey,
+  }
+}

packages/sanity/src/core/store/key-value/serverKeyValueStore.ts

@@ -0,0 +1,49 @@
+import {type SanityClient} from '@sanity/client'
+import {isEqual} from 'lodash'
+import {concat, type Observable, Subject} from 'rxjs'
+import {distinctUntilChanged, filter, map} from 'rxjs/operators'
+
+import {createServerStorage} from './storage/serverStorage'
+import {type KeyValueStore, type KeyValueStoreValue} from './types'
+
+export function createServerKeyValueStore({client}: {client: SanityClient}): KeyValueStore {
+  const serverStorage = createServerStorage({client})
+
+  const events$ = new Subject<{
+    type: 'optimistic' | 'commit'
+    key: string
+    value: KeyValueStoreValue
+  }>()
+
+  function getKey(key: string) {
+    return serverStorage.getKey(key)
+  }
+
+  function setKey(key: string, value: KeyValueStoreValue) {
+    events$.next({type: 'optimistic', key, value})
+
+    /*
+     * The backend returns the result of the set operation, so we can just pass that along.
+     * Most utils do not use it (they will take advantage of local state first) but it reflects the
+     * backend function and could be useful for debugging.
+     */
+    return serverStorage.setKey(key, value).then((storedValue) => {
+      events$.next({type: 'commit', key, value: storedValue})
+      return storedValue
+    })
+  }
+
+  return {
+    getKey(key: string): Observable<KeyValueStoreValue | null> {
+      return concat(
+        getKey(key),
+        events$.pipe(
+          filter((event) => event.key === key),
+          map((event) => event.value),
+          distinctUntilChanged(isEqual),
+        ),
+      )
+    },
+    setKey,
+  }
+}

packages/sanity/src/core/store/key-value/storage/localStoreStorage.ts

@@ -0,0 +1,38 @@
+import {supportsLocalStorage} from '../../../util/supportsLocalStorage'
+import {type KeyValueStoreValue} from '../types'
+import {createMemoryStorage} from './memoryStorage'
+
+function tryParse(val: string) {
+  try {
+    return JSON.parse(val)
+  } catch (err) {
+    // eslint-disable-next-line no-console
+    console.warn(`Failed to parse settings: ${err.message}`)
+    return null
+  }
+}
+
+function createLocalStoreStorage() {
+  if (!supportsLocalStorage) {
+    return createMemoryStorage()
+  }
+
+  function getKey(key: string): KeyValueStoreValue | null {
+    const val = localStorage.getItem(key)
+
+    return val === null ? null : tryParse(val)
+  }
+
+  const setKey = function (key: string, nextValue: KeyValueStoreValue) {
+    // Can't stringify undefined, and nulls are what
+    // `getItem` returns when key does not exist
+    if (typeof nextValue === 'undefined' || nextValue === null) {
+      localStorage.removeItem(key)
+    } else {
+      localStorage.setItem(key, JSON.stringify(nextValue))
+    }
+  }
+  return {getKey, setKey}
+}
+
+export const localStoreStorage = createLocalStoreStorage()

packages/sanity/src/core/store/key-value/storage/memoryStorage.ts

@@ -0,0 +1,13 @@
+import {type KeyValueStoreValue} from '../types'
+
+export function createMemoryStorage() {
+  const DB = Object.create(null)
+  return {
+    getKey(key: string): KeyValueStoreValue | null {
+      return DB[key] || null
+    },
+    setKey(key: string, value: KeyValueStoreValue) {
+      DB[key] = value
+    },
+  }
+}