恢复存储 API

恢复存储 API 决定未保存内容的副本放在哪里。把一个存储传给 createDocumentEngine 的 recovery 配置项即可。恢复的具体行为见恢复指南。

内置存储

function createIndexedDbRecovery(options?: IndexedDbRecoveryOptions): RecoveryStore

IndexedDB copies while the user edits, plus a synchronous localStorage copy when the page closes.

function createMemoryRecovery(): RecoveryStore

An in-memory recovery store for tests.

Name	Type	Default	Description
databaseName	string	—	The IndexedDB database name.
storeName	string	—	The object store name.

实现这个恢复存储 API，就能把副本放到别的地方：

Name	Type	Default	Description
get*	(key: string): Promise<unknown>	—	Reads a copy.
set*	(key: string, value: unknown): Promise<void>	—	Writes a copy.
setNow	(key: string, value: unknown): void	—	Writes a copy synchronously, for the moment the page closes.
delete*	(key: string): Promise<void>	—	Deletes a copy.
keys*	(): Promise<string[]>	—	Lists the stored keys.

setNow 是可选的。页面关闭时浏览器不会等待异步写入，所以如果有 setNow，引擎会在那一刻调用它。createIndexedDbRecovery 用 localStorage 来实现它。

Name	Type	Default	Description
store*	RecoveryStore	—	Where copies are kept, such as `createIndexedDbRecovery()`.
interval	number	2000	Write a copy at most once every this many milliseconds while there are unsaved changes.

使用恢复存储 API 的引擎方法，比如 getRecoverableDocuments 和 restoreRecovery，列在 DocumentEngine 页面。