+// https://github.com/kennygomdori/AsyncIndexedDB
+
+export default class AsyncIndexedDB {
+ // return opened database with schema definitions given.
+ constructor(db_name, schema, version) {
+ this.name = db_name;
+ this.schema = schema; // upgrade callback
+ if (version) this.version = version;
+ this.db = null;
+ Object.seal(this);
+ }
+
+ open() {
+ return new Promise((resolve, reject) => {
+ const db_request = self.indexedDB.open(this.name, this.version);
+ const schema = this.schema;
+ db_request.onerror = (event) => reject(event);
+ db_request.onsuccess = (event) => {
+ this.db = db_request.result;
+ resolve(this);
+ }
+ db_request.onupgradeneeded = function (event) {
+ schema(this.result)
+ };
+ })
+ }
+
+ // returns an ObjectStore proxy whose methods are awaitable.
+ query(objectStoreName, mode = "readwrite", oncomplete, onerror) {
+ // e.g. await this.query().getAll()
+ const transaction = this.db.transaction(objectStoreName, mode);
+ if (oncomplete instanceof Function) transaction.oncomplete = oncomplete;
+ if (onerror instanceof Function) transaction.onerror = onerror;
+ return AsyncIndexedDB.proxy(transaction.objectStore(objectStoreName))
+ }
+
+ static proxy(obj) {
+ // convert an IDBObjectStore and IDBIndex to an ObjectStore proxy whose methods are awaitable.
+ return new Proxy(obj, {
+ get: function (obj, prop) {
+ if (!(obj[prop] instanceof Function)) return obj[prop];
+ return function (...params) {
+ const request = obj[prop](...params);
+ if (request instanceof IDBIndex)
+ return AsyncIndexedDB.proxy(obj.index(...params));
+ // When a cursor supposed to be returned, return an AsyncIterable instead.
+ // e.g. for await (let {key, value, primaryKey} of await this.query().openCursor()) { ... }
+ return new Promise((resolve, reject) => {
+ request.onsuccess = e => {
+ let result = request.result;
+ if (result instanceof IDBCursor)
+ resolve({
+ request,
+ cursor: result,
+ [Symbol.asyncIterator]: async function* () {
+ let promise;
+ while (result) {
+ yield {key: result.key, value: result.value, primaryKey: result.primaryKey};
+ promise = new Promise((resolve, reject) => {
+ request.onsuccess = e => resolve()
+ request.onerror = e => reject(e);
+ });
+ result.continue();
+ await promise;
+ result = request.result
+ }
+ }
+ });
+ else
+ // functions that do not return a cursor or an index are just turned into Promises.
+ resolve(result);
+ }
+ request.onerror = e => reject(e);
+ });
+ }
+ },
+ });
+ }
+
+ async export(query, keyRange, count) {
+ // Serialize IndexedDB in [[objectStoreName1, [..objects], [objectStoreName2, [..objects], ...] that can be easily turned into a Map.
+ return JSON.stringify(await Promise.all([...this.db.objectStoreNames].map(
+ async objectStorename => {
+ const query = await this.query(objectStorename);
+ if (query.keyPath === null)
+ return [objectStorename, query.getAll(keyRange, count)]
+ }
+ )))
+ }
+
+ async import(data, keyPaths) {
+ // Need to back up the original before import in case of error.
+ // data validation may be required.
+ data = JSON.parse(data);
+ await Promise.all(data.map(async ([objectStoreName, entries]) => {
+ let query = this.query(objectStoreName);
+ if (query.keyPath === null) {
+ let keyPath = keyPaths[objectStoreName];
+ if (keyPath === undefined)
+ throw `ObjectStore '${query.name}' does not have a KeyPath. Call import(data, {[objectStoreName]:[keyPath]}).`
+ for (let obj of entries) {
+ const key = obj[keyPath];
+ if (key !== undefined) throw `ObjectStore '${query.name}' entry '${obj}' is missing its key.`
+ await query.put(obj, key);
+ }
+ } else {
+ for (let obj of entries) await query.put(obj);
+ }
+ }))
+ }
+
+ async clear() {
+ return new Promise((resolve, reject) => {
+ const request = self.indexedDB.deleteDatabase(this.name);
+ request.onsuccess = resolve;
+ request.onerror = reject;
+ })
+ }
+}
projects / ntbd-parcels / .git / commitdiff