@tsonic/efcore

TypeScript type definitions for Entity Framework Core 10 (Microsoft.EntityFrameworkCore.*) for use with the Tsonic compiler (TypeScript → .NET).

This package is generated by tsbindgen from the official NuGet assemblies and is intended to give you an editor-friendly, strongly typed surface while compiling to real EF Core APIs.

What this package is (and isn’t)

• ✅ It is a TypeScript type package (.d.ts) + ESM stubs for the EF Core assemblies.
• ❌ It is not a JavaScript runtime implementation of EF Core (the .js files are module stubs for type-only use).
• ✅ You still need the actual .NET assemblies via NuGet in your Tsonic workspace (see below).

Install (types)

npm install @tsonic/efcore @tsonic/dotnet @tsonic/core

Use with Tsonic (recommended)

If you want a deterministic “one command” setup for both the .NET assemblies and the TypeScript bindings, use tsonic add nuget and pass this package as the types argument:

tsonic add nuget Microsoft.EntityFrameworkCore <version> @tsonic/efcore

If you omit the @tsonic/efcore argument, Tsonic will generate bindings locally instead.

Providers

Pick the provider that matches your database:

• SQLite: @tsonic/efcore-sqlite
• SQL Server: @tsonic/efcore-sqlserver
• PostgreSQL (Npgsql): @tsonic/efcore-npgsql

Example:

tsonic add nuget Microsoft.EntityFrameworkCore.Sqlite <version> @tsonic/efcore-sqlite

Imports

The package is shipped as ESM. Import EF Core namespaces via explicit module paths:

import { DbContext, DbContextOptions, DbSet } from "@tsonic/efcore/Microsoft.EntityFrameworkCore.js";

Provider-specific APIs come from the provider package:

import { SqliteDbContextOptionsBuilderExtensions } from "@tsonic/efcore-sqlite/Microsoft.EntityFrameworkCore.js";

LINQ + EF extension methods (idiomatic queries)

EF Core relies heavily on extension methods (LINQ operators like Where/Select and EF async operators like CountAsync/ToArrayAsync).

In Tsonic, you opt into a “C# using semantics” extension surface by wrapping the receiver with asinterface<...> and the generated ExtensionMethods helpers:

import { asinterface } from "@tsonic/core/lang.js";
import type { ExtensionMethods as Linq } from "@tsonic/dotnet/System.Linq.js";
import type { ExtensionMethods as Ef } from "@tsonic/efcore/Microsoft.EntityFrameworkCore.js";
import type { DbSet } from "@tsonic/efcore/Microsoft.EntityFrameworkCore.js";

type DbSetQuery<T> = Ef<Linq<DbSet<T>>>;

// Example: turn a DbSet<T> into something that has LINQ + EF async operators.
const q = asinterface<DbSetQuery<PostEntity>>(db.posts);

const pageviews = await q.Where((p) => p.Published === true).CountAsync();
const rows = await q.Where((p) => p.Published === true).ToArrayAsync();

You can always call extension methods via their static classes as well, but the pattern above gives you the most idiomatic “instance-style” call sites.

Example

Minimal DbContext + options:

import { DbContext, DbContextOptions, DbContextOptionsBuilder, DbSet } from "@tsonic/efcore/Microsoft.EntityFrameworkCore.js";
import { SqliteDbContextOptionsBuilderExtensions } from "@tsonic/efcore-sqlite/Microsoft.EntityFrameworkCore.js";

export class BlogDbContext extends DbContext {
  get posts(): DbSet<PostEntity> {
    return this.Set<PostEntity>();
  }

  constructor(options: DbContextOptions) {
    super(options);
  }
}

export const createDbOptions = (dbPath: string): DbContextOptions => {
  const optionsBuilder = new DbContextOptionsBuilder();
  SqliteDbContextOptionsBuilderExtensions.UseSqlite(optionsBuilder, `Data Source=${dbPath}`);
  return optionsBuilder.Options;
};

Versioning

This repo is versioned by .NET major:

• .NET 10 → npm: @tsonic/[email protected]

Development (regenerating bindings)

This repo is generated from NuGet assemblies:

npm install
npm run generate:10

License

MIT