tldraw/packages/www/hooks/usePersistence.tsx
2021-08-10 17:12:55 +01:00

93 lines
2.7 KiB
TypeScript

import * as React from "react"
import { openDB, DBSchema } from "idb"
import type { TLDrawDocument } from "@tldraw/tldraw"
interface TLDatabase extends DBSchema {
documents: {
key: string
value: TLDrawDocument
}
}
/**
* Persist a value in indexdb. This hook is designed to be used primarily through
* its methods, `setValue` and `forceUpdate`. The `setValue` method will update the
* value in the database, howeever it will NOT cause the hook's component to update.
* The `forceUpdate` method will cause the component to update with the latest value
* in the database.
*
* ### Example
*
*```ts
* const {status, value, setValue, forceUpdate} = usePersistence()
*```
*/
export function usePersistence(id: string, doc: TLDrawDocument) {
// eslint-disable-next-line react-hooks/exhaustive-deps
const [status, setStatus] = React.useState<"loading" | "ready">("loading")
const [value, _setValue] = React.useState<TLDrawDocument | null>(null)
// A function that other parts of the program can use to manually update
// the state to the latest value in the database.
const forceUpdate = React.useCallback(() => {
_setValue(null)
setStatus("loading")
openDB<TLDatabase>("db", 1).then((db) =>
db.get("documents", id).then((v) => {
if (!v) throw Error(`Could not find document with id: ${id}`)
_setValue(v)
setStatus("ready")
})
)
}, [id])
// A function that other parts of the program can use to manually set the
// value in the database.
const setValue = React.useCallback(
(doc: TLDrawDocument) => {
openDB<TLDatabase>("db", 1).then((db) => db.put("documents", doc, id))
},
[id]
)
// Whenever the id or doc changes, save the new value to the database and update
// the state.
React.useEffect(() => {
async function handleLoad() {
const db = await openDB<TLDatabase>("db", 1, {
upgrade(db) {
db.createObjectStore("documents")
},
})
let savedDoc: TLDrawDocument
try {
const restoredDoc = await db.get("documents", id)
if (!restoredDoc) throw Error("No document")
savedDoc = restoredDoc
restoredDoc.pageStates = Object.fromEntries(
Object.entries(restoredDoc.pageStates).map(([pageId, pageState]) => [
pageId,
{
...pageState,
hoveredId: undefined,
editingId: undefined,
},
])
)
} catch (e) {
await db.put("documents", doc, id)
savedDoc = doc
}
_setValue(savedDoc)
setStatus("ready")
}
handleLoad()
}, [id, doc])
return { value, status, setValue, forceUpdate }
}