simpleDB.js

(function (global) {
    var SECRET = Object.create(null);
    var DB_PREFIX = '$SimpleDB$';
    var STORE = 'store';

    function SimpleDBFactory(secret) {
        if (secret !== SECRET) throw TypeError('Invalid constructor');
    }
    SimpleDBFactory.prototype = {
        open: function (name) {
            return new Promise(function (resolve, reject) {
                var request = indexedDB.open(DB_PREFIX + name);
                request.onupgradeneeded = function () {
                    var db = request.result;
                    db.createObjectStore(STORE);
                };
                request.onsuccess = function () {
                    var db = request.result;
                    resolve(new SimpleDB(SECRET, name, db));
                };
                request.onerror = function () {
                    reject(request.error);
                };
            });
        },
        delete: function (name) {
            return new Promise(function (resolve, reject) {
                var request = indexedDB.deleteDatabase(DB_PREFIX + name);
                request.onsuccess = function () {
                    resolve(undefined);
                };
                request.onerror = function () {
                    reject(request.error);
                };
            });
        }
    };

    function SimpleDB(secret, name, db) {
        if (secret !== SECRET) throw TypeError('Invalid constructor');
        this._name = name;
        this._db = db;
    }
    SimpleDB.cmp = indexedDB.cmp;
    SimpleDB.prototype = {
        get name() {
            return this._name;
        },
        get: function (key) {
            var that = this;
            return new Promise(function (resolve, reject) {
                var tx = that._db.transaction(STORE, 'readwrite');
                var store = tx.objectStore(STORE);
                var req = store.get(key);
                // NOTE: Could also use req.onsuccess/onerror
                tx.oncomplete = function () { resolve(req.result); };
                tx.onabort = function () { reject(tx.error); };
            });
        },
        set: function (key, value) {
            var that = this;
            return new Promise(function (resolve, reject) {
                var tx = that._db.transaction(STORE, 'readwrite');
                var store = tx.objectStore(STORE);
                var req = store.put(value, key);
                tx.oncomplete = function () { resolve(undefined); };
                tx.onabort = function () { reject(tx.error); };
            });
        },
        delete: function (key) {
            var that = this;
            return new Promise(function (resolve, reject) {
                var tx = that._db.transaction(STORE, 'readwrite');
                var store = tx.objectStore(STORE);
                var req = store.delete(key);
                tx.oncomplete = function () { resolve(undefined); };
                tx.onabort = function () { reject(tx.error); };
            });
        },
        clear: function () {
            var that = this;
            return new Promise(function (resolve, reject) {
                var tx = that._db.transaction(STORE, 'readwrite');
                var store = tx.objectStore(STORE);
                var request = store.clear();
                tx.oncomplete = function () { resolve(undefined); };
                tx.onabort = function () { reject(tx.error); };
            });
        },
        forEach: function (callback, options) {
            var that = this;
            return new Promise(function (resolve, reject) {
                options = options || {};
                var tx = that._db.transaction(STORE, 'readwrite');
                var store = tx.objectStore(STORE);
                var request = store.openCursor(
                    options.range,
                    options.direction === 'reverse' ? 'prev' : 'next');
                request.onsuccess = function () {
                    var cursor = request.result;
                    if (!cursor) return;
                    try {
                        var terminate = callback(cursor.key, cursor.value);
                        if (!terminate) cursor.continue();
                    } catch (ex) {
                        tx.abort(); // ???
                    }
                };
                tx.oncomplete = function () { resolve(undefined); };
                tx.onabort = function () { reject(tx.error); };
            });
        },
        getMany: function (keys) {
            var that = this;
            return new Promise(function (resolve, reject) {
                var tx = that._db.transaction(STORE, 'readwrite');
                var store = tx.objectStore(STORE);
                var results = [];
                for (var key of keys) {
                    store.get(key).onsuccess(function (result) {
                        results.push(result);
                    });
                }
                tx.oncomplete = function () { resolve(results); };
                tx.onabort = function () { reject(tx.error); };
            });
        },
        setMany: function (entries) {
            var that = this;
            return new Promise(function (resolve, reject) {
                var tx = that._db.transaction(STORE, 'readwrite');
                var store = tx.objectStore(STORE);
                for (var entry of entries) {
                    store.put(entry.value, entry.key);
                }
                tx.oncomplete = function () { resolve(undefined); };
                tx.onabort = function () { reject(tx.error); };
            });
        },
        deleteMany: function (keys) {
            var that = this;
            return new Promise(function (resolve, reject) {
                var tx = that._db.transaction(STORE, 'readwrite');
                var store = tx.objectStore(STORE);
                for (var key of keys)
                    store.delete(key);
                tx.oncomplete = function () { resolve(undefined); };
                tx.onabort = function () { reject(tx.error); };
            });
        }
    };

    global.simpleDB = new SimpleDBFactory(SECRET);
    global.SimpleDBKeyRange = IDBKeyRange;
}(self));