A client-side key-value store with support for indexes.

IndexedDB is a web standard API for client-side storage ofstructured data. By storing data on the client in an IndexedDB,apps can get advantages such as faster performance andpersistence.

In IndexedDB, each record is identified by a unique index or key,making data retrieval speedy.You can store structured data,such as images, arrays, and maps using IndexedDB.The standard does not specify size limits for individual data itemsor for the database itself, but browsers may impose storage limits.

Using indexed_db

The classes in this library provide an interfaceto the browser's IndexedDB, if it has one.To use this library in your code:

import 'dart:indexed_db';

IndexedDB is almost universally supported in modern web browsers, buta web app can determine if the browser supports IndexedDBwithIdbFactory.supported:

if (IdbFactory.supported)  // Use indexeddb.else  // Find an alternative.

Access to the browser's IndexedDB is provided by the app's top-levelWindow object, which your code can refer to withwindow.indexedDB.So, for example,here's how to use window.indexedDB to open a database:

Future open() {  return window.indexedDB.open('myIndexedDB',      version: 1,      onUpgradeNeeded: _initializeDatabase)    .then(_loadFromDB);}void _initializeDatabase(VersionChangeEvent e) {  ...}Future _loadFromDB(Database db) {  ...}

All data in an IndexedDB is stored within anObjectStore.To manipulate the database useTransactions.

Other resources

Other options for client-side data storage include:

• Window.localStorage—abasic mechanism that stores data as aMap,and where both the keys and the values are strings.

MDN providesAPIdocumentation.

Classes

Cursor

CursorWithValue

Database

An indexed database object for storing client-side datain web apps.

IdbFactory

Index

KeyRange

ObjectStore

Observation

Observer

ObserverChanges

OpenDBRequest

Request

Transaction

VersionChangeEvent

Typedefs

ObserverCallback= void Function(ObserverChangeschanges)