View Source DenoRider

DenoRider is an Elixir library that embeds the Deno runtime via Rustler. It is a performant way to run JavaScript in Elixir and it doesn't depend on external executables.

Installation

Add :deno_rider to your mix.exs:

{:deno_rider, "~> 0.1"}

Add DenoRider to your application's supervisor:

# lib/my_app/application.ex
def start(_type, _args) do
  children = [
    ...,
    DenoRider
  ]

  Supervisor.start_link(children, strategy: :one_for_one, name: MyApp.Supervisor)
end

See start_link/1 for more information about options when starting DenoRider.

Precompiled NIFs

DenoRider provides precompiled NIFs (via RustlerPrecompiled) for the following targets:

• aarch64-apple-darwin
• aarch64-unknown-linux-gnu
• x86_64-apple-darwin
• x86_64-pc-windows-msvc
• x86_64-unknown-linux-gnu

Contributions for precompiling DenoRider to more targets are welcome!

You can build DenoRider yourself by setting the environment variable DENO_RIDER_BUILD to true.

Usage

To run JavaScript code with DenoRider, you use eval. For example:

iex> DenoRider.eval("1 + 2")
{:ok, 3}
iex> DenoRider.eval("globalThis.foo = 'bar'")
{:ok, "bar"}
iex> DenoRider.eval("globalThis.foo")
{:ok, "bar"}

See eval/1 and eval/2 for different ways of running JavaScript code.

If you don't want to run DenoRider as a process, you can manage the runtime manually:

iex> {:ok, runtime} = DenoRider.start_runtime() |> Task.await()
{:ok, %DenoRider.Runtime{reference: #Reference<0.328177905.1027473408.14690>}}
iex> DenoRider.eval("1 + 2", runtime: runtime) |> Task.await()
{:ok, 3}
iex> DenoRider.stop_runtime(runtime) |> Task.await()
{:ok, nil}

Read the full documentation for more information.

FAQ

When should I use DenoRider?

If you need to run JavaScript from Elixir, you can give DenoRider a try. Some common use cases for that is for example server-side rendering of React or wrapping a JavaScript library in Elixir.

What makes DenoRider different from other ways of calling JavaScript from Elixir?

Since DenoRider embeds the Deno runtime, you don't need any external executables (such as node) and the latency for your JavaScript calls is very low.

When shouldn't I use DenoRider?

One reason could be that you want to use another JavaScript runtime, such as Node or Bun. Or if you want to use Deno features that DenoRider doesn't provide.

What are some common pitfalls?

There's currently no npm integration, which means that if you want to use an npm package you first need to convert it into something that's consumable by DenoRider. To do that you can use Rollup, for example.

License

DenoRider is released under the MIT license. See the LICENSE file for more information.