57 lines
1.9 KiB
JavaScript
57 lines
1.9 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.exists = exists;
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/*
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Copyright 2019 New Vector Ltd
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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/**
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* Check if an IndexedDB database exists. The only way to do so is to try opening it, so
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* we do that and then delete it did not exist before.
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*
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* @param indexedDB - The `indexedDB` interface
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* @param dbName - The database name to test for
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* @returns Whether the database exists
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*/
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function exists(indexedDB, dbName) {
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return new Promise((resolve, reject) => {
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let exists = true;
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const req = indexedDB.open(dbName);
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req.onupgradeneeded = () => {
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// Since we did not provide an explicit version when opening, this event
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// should only fire if the DB did not exist before at any version.
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exists = false;
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};
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req.onblocked = () => reject(req.error);
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req.onsuccess = () => {
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const db = req.result;
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db.close();
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if (!exists) {
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// The DB did not exist before, but has been created as part of this
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// existence check. Delete it now to restore previous state. Delete can
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// actually take a while to complete in some browsers, so don't wait for
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// it. This won't block future open calls that a store might issue next to
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// properly set up the DB.
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indexedDB.deleteDatabase(dbName);
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}
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resolve(exists);
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};
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req.onerror = () => reject(req.error);
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});
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}
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//# sourceMappingURL=indexeddb-helpers.js.map
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