This is a tiny (~1.15k) library that mostly mirrors the IndexedDB API, but with small improvements that make a big difference to usability.
npm install idb
Then, assuming you're using a module-compatible system (like webpack, Rollup etc):
import { openDB, deleteDB, wrap, unwrap } from 'idb';
async function doDatabaseStuff() {
const db = await openDB(…);
}
Or, use it directly via unpkg:
<script type="module">
import { openDB, deleteDB, wrap, unwrap } from 'https://unpkg.com/idb?module';
async function doDatabaseStuff() {
const db = await openDB(…);
}
</script>
This is a rewrite from 3.x with substantial changes. See details.
This method opens a database, and returns a promise for an enhanced IDBDatabase
.
const db = await openDB(name, version, {
upgrade(db, oldVersion, newVersion, transaction) {
// …
},
blocked() {
// …
},
blocking() {
// …
}
});
name
: Name of the database.version
: Schema version.upgrade
(optional): Called if this version of the database has never been opened before. Use it to specify the schema for the database. This is similar to theupgradeneeded
event in plain IndexedDB.db
: An enhancedIDBDatabase
.oldVersion
: Last version of the database opened by the user.newVersion
: Whatever new version you provided.transaction
: An enhanced transaction for this upgrade. This is useful if you need to get data from other stores as part of a migration.
blocked
(optional): Called if there are older versions of the database open on the origin, so this version cannot open. This is similar to theblocked
event in plain IndexedDB.blocking
(optional): Called if this connection is blocking a future version of the database from opening. This is similar to theversionchange
event in plain IndexedDB.
Deletes a database.
await deleteDB(name);
name
: Name of the database.
Takes an enhanced IndexedDB object and returns the plain unmodified one.
const unwrapped = unwrap(wrapped);
This is useful if, for some reason, you want to drop back into plain IndexedDB. Promises will also be converted back into IDBRequest
objects.
Takes an IDB object and returns a version enhanced by this library.
const wrapped = wrap(unwrapped);
This is useful if some third party code gives you an IDBDatabase
object and you want it to have the features of this library.
This doesn't work with IDBCursor
, due to missing primitives. Also, if you wrap an IDBTransaction
, tx.store
and tx.objectStoreNames
won't work in Edge. To avoid these issues, wrap the IDBDatabase
object, and use the wrapped object to create a new transaction.
Once you've opened the database the API is the same as IndexedDB, except for a few changes to make things easier.
Firstly, any method that usually returns an IDBRequest
object will now return a promise for the result.
const store = db.transaction(storeName).objectStore(storeName);
const value = await store.get(key);
The library turns all IDBRequest
objects into promises, but it doesn't know in advance which methods may return promises.
As a result, methods such as store.put
may throw instead of returning a promise.
If you're using async functions, there's no observable difference.
TL;DR: Do not await
other things between the start and end of your transaction, otherwise the transaction will close before you're done.
An IDB transaction auto-closes if it doesn't have anything left do once microtasks have been processed. As a result, this works fine:
const tx = db.transaction('keyval', 'readwrite');
const store = tx.objectStore('keyval');
const val = await store.get('counter') || 0;
store.put(val + 1, 'counter');
await tx.done;
But this doesn't:
const tx = db.transaction('keyval', 'readwrite');
const store = tx.objectStore('keyval');
const val = await store.get('counter') || 0;
// This is where things go wrong:
const newVal = await fetch('/increment?val=' + val);
// And this throws an error:
store.put(newVal, 'counter');
await tx.done;
In this case, the transaction closes while the browser is fetching, so store.put
fails.
It's common to create a transaction for a single action, so helper methods are included for this:
// Get a value from a store:
const value = await db.get(storeName, key);
// Set a value in a store:
await db.put(storeName, value, key);
The shortcuts are: get
, getKey
, getAll
, getAllKeys
, count
, put
, add
, delete
, and clear
. Each method takes a storeName
argument, the name of the object store, and the rest of the arguments are the same as the equivalent IDBObjectStore
method.
These methods depend on the same methods on IDBObjectStore
, therefore getKey
, getAll
, and getAllKeys
are missing in Edge.
The shortcuts are: getFromIndex
, getKeyFromIndex
, getAllFromIndex
, getAllKeysFromIndex
, and countFromIndex
.
// Get a value from an index:
const value = await db.getFromIndex(storeName, indexName, key);
Each method takes storeName
and indexName
arguments, followed by the rest of the arguments from the equivalent IDBIndex
method. Again, these methods depend on the equivalent methods on IDBIndex
, so Edge does not support getKeyFromIndex
, getAllFromIndex
, or getAllKeysFromIndex
.
If a transaction involves a single store, the store
property will reference that store.
const tx = db.transaction('whatever');
const store = tx.store;
If a transaction involves multiple stores, tx.store
is undefined, you need to use tx.objectStore(storeName)
to get the stores.
Transactions have a .done
promise which resolves when the transaction completes successfully, and otherwise rejects with the transaction error.
const tx = db.transaction(storeName, 'readwrite');
tx.store.put('foo', 'bar');
await tx.done;
Cursor advance methods (advance
, continue
, continuePrimaryKey
) return a promise for the cursor, or null if there are no further values to provide.
let cursor = await db.transaction(storeName).store.openCursor();
while (cursor) {
console.log(cursor.key, cursor.value);
cursor = await cursor.continue();
}
Async iterator support isn't included by default (Edge doesn't support them). To include them, import idb/with-async-ittr.js
instead of idb
(this increases the library size to ~1.37k):
import { openDB } from 'idb/with-async-ittr.js';
Now you can iterate over stores, indexes, and cursors:
const tx = db.transaction(storeName);
for await (const cursor of tx.store) {
// …
}
Each yielded object is an IDBCursor
. You can optionally use the advance methods to skip items (within an async iterator they return void):
const tx = db.transaction(storeName);
for await (const cursor of tx.store) {
console.log(cursor.value);
// Skip the next item
cursor.advance(2);
}
If you don't manually advance the cursor, cursor.continue()
is called for you.
Stores and indexes also have an iterate
method which has the same signature as openCursor
, but returns an async iterator:
const index = db.transaction('books').store.index('author');
for await (const cursor of index.iterate('Douglas Adams')) {
console.log(cursor.value);
}
This is very similar to localStorage
, but async. If this is all you need, you may be interested in idb-keyval. You can always upgrade to this library later.
const dbPromise = openDB('keyval-store', 1, {
upgrade(db) {
db.createObjectStore('keyval');
}
});
const idbKeyval = {
async get(key) {
return (await dbPromise).get('keyval', key);
},
async set(key, val) {
return (await dbPromise).put('keyval', val, key);
},
async delete(key) {
return (await dbPromise).delete('keyval', key);
},
async clear() {
return (await dbPromise).clear('keyval');
},
async keys() {
return (await dbPromise).getAllKeys('keyval');
},
};
async function demo() {
const db = await openDB('Articles', 1, {
upgrade(db) {
// Create a store of objects
const store = db.createObjectStore('articles', {
// The 'id' property of the object will be the key.
keyPath: 'id',
// If it isn't explicitly set, create a value by auto incrementing.
autoIncrement: true,
});
// Create an index on the 'date' property of the objects.
store.createIndex('date', 'date');
},
});
// Add an article:
await db.add('articles', {
title: 'Article 1',
date: new Date('2019-01-01'),
body: '…',
});
// Add multiple articles in one transaction:
{
const tx = db.transaction('articles', 'readwrite');
tx.store.add({
title: 'Article 2',
date: new Date('2019-01-01'),
body: '…',
});
tx.store.add({
title: 'Article 3',
date: new Date('2019-01-02'),
body: '…',
});
await tx.done;
}
// Get all the articles in date order:
console.log(await db.getAllFromIndex('articles', 'date'));
// Add 'And, happy new year!' to all articles on 2019-01-01:
{
const tx = db.transaction('articles', 'readwrite');
const index = tx.store.index('date');
for await (const cursor of index.iterate(new Date('2019-01-01'))) {
const article = { ...cursor.value };
article.body += ' And, happy new year!';
cursor.update(article);
}
await tx.done;
}
}
This library is fully typed, and you can improve things by providing types for your database:
import { openDB, DBSchema } from 'idb';
interface MyDB extends DBSchema {
'favourite-number': {
key: string,
value: number,
},
'products': {
value: {
name: string,
price: number,
productCode: string,
},
key: string,
indexes: { 'by-price': number },
}
}
async function demo() {
const db = await openDB<MyDB>('my-db', 1, {
upgrade(db) {
db.createObjectStore('favourite-number');
const productStore = db.createObjectStore('products', { keyPath: 'productCode' });
productStore.createIndex('by-price', 'price');
}
});
// This works
await db.put('favourite-number', 7, 'Jen');
// This fails at compile time, as the 'favourite-number' store expects a number.
await db.put('favourite-number', 'Twelve', 'Jake');
}
To define types for your database, extend DBSchema
with an interface where the keys are the names of your object stores.
For each value, provide an object where value
is the type of values within the store, and key
is the type of keys within the store.
Optionally, indexes
can contain a map of index names, to the type of key within that index.
Provide this interface when calling openDB
, and from then on your database will be strongly typed. This also allows your IDE to autocomplete the names of stores and indexes.
If you call openDB
without providing types, your database will use basic types. However, sometimes you'll need to interact with stores that aren't in your schema, perhaps during upgrades. In that case you can cast.
Let's say we were renaming the 'favourite-number' store to 'fave-nums':
import { openDB, DBSchema, IDBPDatabase } from 'idb';
interface MyDBV1 extends DBSchema {
'favourite-number': { key: string, value: number },
}
interface MyDBV2 extends DBSchema {
'fave-num': { key: string, value: number },
}
const db = await openDB<MyDBV2>('my-db', 2, {
async upgrade(db, oldVersion) {
// Cast a reference of the database to the old schema.
const v1Db = db as unknown as IDBPDatabase<MyDBV1>;
if (oldVersion < 1) {
v1Db.createObjectStore('favourite-number');
}
if (oldVersion < 2) {
const store = v1Db.createObjectStore('favourite-number');
store.name = 'fave-num';
}
}
});
You can also cast to a typeless database by omiting the type, eg db as IDBPDatabase
.
Note: Types like IDBPDatabase
are used by TypeScript only. The implementation uses proxies under the hood.