CLR Bindings and Interop

Tsonic does not hide CLR interop behind a JS-like illusion. It keeps it explicit and package-based.

Import CLR APIs explicitly

import { Console } from "@tsonic/dotnet/System.js";
import { Enumerable } from "@tsonic/dotnet/System.Linq.js";

export function main(): void {
  const xs = [1, 2, 3];
  const filtered = Enumerable.Where(xs, (x: number): boolean => x > 1);
  Console.WriteLine(filtered.Count().ToString());
}

Where these packages come from

Generated CLR binding packages are produced by tsbindgen.

Examples:

• @tsonic/dotnet
• @tsonic/aspnetcore
• @tsonic/microsoft-extensions
• @tsonic/efcore

Add external CLR dependencies

Tsonic supports three main CLR input paths.

Framework references

tsonic add framework Microsoft.AspNetCore.App @tsonic/aspnetcore

Use this for shared frameworks such as ASP.NET Core.

NuGet packages

tsonic add nuget Microsoft.EntityFrameworkCore 10.0.0
tsonic restore

Use this for package references that should live in tsonic.workspace.json.

The corresponding Tsonic binding package is then imported explicitly. Example:

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

Local DLLs

tsonic add package ./libs/MyCompany.MyLib.dll

If you do not provide a types package explicitly, Tsonic can generate one with tsbindgen.

Typical interop patterns

BCL usage

import { Console } from "@tsonic/dotnet/System.js";
import { List } from "@tsonic/dotnet/System.Collections.Generic.js";

ASP.NET Core usage

import { WebApplication } from "@tsonic/aspnetcore/Microsoft.AspNetCore.Builder.js";

EF Core usage

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

Why the docs separate this from first-party packages

The current architecture has two distinct kinds of packages:

• authored first-party source packages like @tsonic/js, @tsonic/nodejs, and @tsonic/express
• generated CLR binding packages produced by tsbindgen

The site now keeps those categories separate because they have different build, ownership, and release flows.