IndexedDB (Blazor WASM)

The Shiny.DocumentDb.IndexedDb package provides an IndexedDB-backed document store for Blazor WebAssembly applications. It implements the full IDocumentStore interface using JavaScript interop — no native dependencies, no file system access required.

When to Use

• Blazor WebAssembly apps that need client-side persistent storage
• Offline-capable progressive web apps (PWAs)
• Browser-based apps where you want the same document store API as your server/mobile code

Installation

dotnet add package Shiny.DocumentDb.IndexedDb

Setup

1. Register with dependency injection in your Blazor WASM Program.cs:

   using Shiny.DocumentDb.IndexedDb;
   
   builder.Services.AddSingleton(new IndexedDbDocumentStoreOptions { DatabaseName = "MyAppDb" });
   builder.Services.AddSingleton<IDocumentStore, IndexedDbDocumentStore>();

   Or with full options:

   builder.Services.AddSingleton(new IndexedDbDocumentStoreOptions
   {
       DatabaseName = "MyAppDb",
       Version = 1
   }.MapTypeToStore<User>()           // dedicated object store
    .MapTypeToStore<Order>("orders")  // explicit store name
   );
   builder.Services.AddSingleton<IDocumentStore, IndexedDbDocumentStore>();

2. Inject and use IDocumentStore in your components:

   @inject IDocumentStore Store
   
   @code {
       private List<User> users = new();
   
       protected override async Task OnInitializedAsync()
       {
           users = (await Store.Query<User>().ToList()).ToList();
       }
   
       private async Task AddUser()
       {
           var user = new User { Name = "Alice", Age = 25 };
           await Store.Insert(user);
           users.Add(user);
       }
   }

Options Reference

Property	Type	Default	Description
DatabaseName	string	(required)	The name of the IndexedDB database
Version	int	1	IndexedDB database version. Increment when adding new object stores
StoreName	string	"documents"	Default object store for unmapped types
TypeNameResolution	TypeNameResolution	ShortName	How type names are stored
JsonSerializerOptions	JsonSerializerOptions?	null	JSON serialization settings
UseReflectionFallback	bool	true	Set to false for AOT safety
Logging	Action<string>?	null	Diagnostic callback

Store-Per-Type Mapping

Similar to table-per-type mapping in SQL providers, you can map document types to dedicated IndexedDB object stores:

builder.Services.AddSingleton(new IndexedDbDocumentStoreOptions
{
    DatabaseName = "MyAppDb"
}.MapTypeToStore<User>()                          // auto-derived store name
 .MapTypeToStore<Order>("orders")                 // explicit store name
 .MapTypeToStore<Sensor>(s => s.DeviceKey)        // custom Id property
);
builder.Services.AddSingleton<IDocumentStore, IndexedDbDocumentStore>();

Supported Operations

The IndexedDB provider supports the full IDocumentStore API:

• Insert, Update, Upsert, BatchInsert
• Get, Remove, Clear
• SetProperty, RemoveProperty
• GetDiff (JSON patch diffing)
• Query<T>() fluent LINQ queries (Where, OrderBy, Paginate, Select, aggregates)
• Count<T>()
• RunInTransaction (operations are batched in a single IndexedDB transaction)

Not Supported

• Raw SQL queries — Query<T>(string whereClause) and QueryStream<T>(string whereClause) throw NotSupportedException. Use the LINQ-based Query<T>() overload instead.
• Spatial queries — IndexedDB does not support R*Tree or GeoJSON indexes.

How It Works

Under the hood, the provider:

1. Opens an IndexedDB database with the configured name and version
2. Creates object stores (with a typeName index) during the upgradeneeded event
3. Stores documents as { key, id, typeName, data, createdAt, updatedAt } records
4. Uses the composite key "{TypeName}:{Id}" as the IndexedDB key path
5. Queries load all documents of a type via the typeName index, then apply LINQ predicates client-side

All IndexedDB operations are performed through a JavaScript ES module (shiny-indexeddb.js) bundled as a static web asset.

SQLite in Blazor WASM

If you need SQL-level query features (raw WHERE clauses, JSON indexes, spatial queries), the existing SQLite provider is also WASM-compatible when paired with SQLitePCLRaw.bundle_wasm:

• WAL pragma is automatically skipped on OperatingSystem.IsBrowser()
• Spatial (R*Tree) is automatically disabled in the browser
• Backup() is marked [UnsupportedOSPlatform("browser")]
• Use Data Source=:memory: or Emscripten OPFS-mounted paths

The IndexedDB provider is lighter (no native WASM SQLite binary) and simpler for most client-side storage scenarios. Choose SQLite-in-WASM only when you need its advanced query capabilities.

Versioning

When you add new type-to-store mappings, increment Version so that the upgradeneeded event fires and creates the new object stores:

opts.Version = 2; // was 1, now creating a new store
opts.MapTypeToStore<NewType>();

IndexedDB handles the schema migration automatically — existing data in other stores is preserved.