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import EventEmitter from 'eventemitter3'
import BroadcastChannel from '#/lib/broadcast'
import {logger} from '#/logger'
import {
defaults,
Schema,
tryParse,
tryStringify,
} from '#/state/persisted/schema'
import {PersistedApi} from './types'
import {normalizeData} from './util'
export type {PersistedAccount, Schema} from '#/state/persisted/schema'
export {defaults} from '#/state/persisted/schema'
const BSKY_STORAGE = 'BSKY_STORAGE'
const broadcast = new BroadcastChannel('BSKY_BROADCAST_CHANNEL')
const UPDATE_EVENT = 'BSKY_UPDATE'
let _state: Schema = defaults
const _emitter = new EventEmitter()
export async function init() {
broadcast.onmessage = onBroadcastMessage
window.onstorage = onStorage
const stored = readFromStorage()
if (stored) {
_state = stored
}
}
init satisfies PersistedApi['init']
export function get<K extends keyof Schema>(key: K): Schema[K] {
return _state[key]
}
get satisfies PersistedApi['get']
export async function write<K extends keyof Schema>(
key: K,
value: Schema[K],
): Promise<void> {
const next = readFromStorage()
if (next) {
// The storage could have been updated by a different tab before this tab is notified.
// Make sure this write is applied on top of the latest data in the storage as long as it's valid.
_state = next
// Don't fire the update listeners yet to avoid a loop.
// If there was a change, we'll receive the broadcast event soon enough which will do that.
}
try {
if (JSON.stringify({v: _state[key]}) === JSON.stringify({v: value})) {
// Fast path for updates that are guaranteed to be noops.
// This is good mostly because it avoids useless broadcasts to other tabs.
return
}
} catch (e) {
// Ignore and go through the normal path.
}
_state = normalizeData({
..._state,
[key]: value,
})
writeToStorage(_state)
broadcast.postMessage({event: {type: UPDATE_EVENT, key}})
broadcast.postMessage({event: UPDATE_EVENT}) // Backcompat while upgrading
}
write satisfies PersistedApi['write']
export function onUpdate<K extends keyof Schema>(
key: K,
cb: (v: Schema[K]) => void,
): () => void {
const listener = () => cb(get(key))
_emitter.addListener('update', listener) // Backcompat while upgrading
_emitter.addListener('update:' + key, listener)
return () => {
_emitter.removeListener('update', listener) // Backcompat while upgrading
_emitter.removeListener('update:' + key, listener)
}
}
onUpdate satisfies PersistedApi['onUpdate']
export async function clearStorage() {
try {
localStorage.removeItem(BSKY_STORAGE)
} catch (e: any) {
// Expected on the web in private mode.
}
}
clearStorage satisfies PersistedApi['clearStorage']
function onStorage() {
const next = readFromStorage()
if (next === _state) {
return
}
if (next) {
_state = next
_emitter.emit('update')
}
}
async function onBroadcastMessage({data}: MessageEvent) {
if (
typeof data === 'object' &&
(data.event === UPDATE_EVENT || // Backcompat while upgrading
data.event?.type === UPDATE_EVENT)
) {
// read next state, possibly updated by another tab
const next = readFromStorage()
if (next === _state) {
return
}
if (next) {
_state = next
if (typeof data.event.key === 'string') {
_emitter.emit('update:' + data.event.key)
} else {
_emitter.emit('update') // Backcompat while upgrading
}
} else {
logger.error(
`persisted state: handled update update from broadcast channel, but found no data`,
)
}
}
}
function writeToStorage(value: Schema) {
const rawData = tryStringify(value)
if (rawData) {
try {
localStorage.setItem(BSKY_STORAGE, rawData)
} catch (e) {
// Expected on the web in private mode.
}
}
}
let lastRawData: string | undefined
let lastResult: Schema | undefined
function readFromStorage(): Schema | undefined {
let rawData: string | null = null
try {
rawData = localStorage.getItem(BSKY_STORAGE)
} catch (e) {
// Expected on the web in private mode.
}
if (rawData) {
if (rawData === lastRawData) {
return lastResult
} else {
const result = tryParse(rawData)
if (result) {
lastRawData = rawData
lastResult = normalizeData(result)
return lastResult
}
}
}
}
|
