[WIP] Working sample of a Suave + Fable + Elmish project with hot reloading
F# JavaScript CSS HTML Shell Batchfile
Latest commit 80e7dbb Feb 24, 2017 @forki forki committed on GitHub Merge pull request #61 from davidpodhola/issues/60
logout in test if logged in



This is a work in progress so it may not work yet as is on your machine.

A web stack designed for developer happiness

The following document describes the Fable + Suave sample project. You can see it running on azure at http://fable-suave.azurewebsites.net.

Development mode

This development stack is designed to be used with minimal tooling. A instance of Visual Studio Code together with the excellent Ionide plugin should be enough.

Start the development mode with:

> build.cmd run // on windows
$ ./build.sh run // on unix

This should download all dependencies like .NET Core SDK, node, ... and start the development server. It will also open a browser with the website on http://localhost:8080.

You can now edit files in src/Server or src/Client and recompile + browser refresh will be triggered automatically.

Development mode

Usually you can just keep this mode running and running. Just edit files, see the browser refreshing and commit + push with git.


Technology stack

Suave on .NET Core

The webserver backend is running as a Suave.io service on .NET Core.

In development mode the server is automatically restarted whenever a file in src/Server is saved.

React/Elmish client

The client is React single page application that uses fable-elmish to provide a scaffold for the code.

The communication to the server is done via HTTPS calls to /api/*. If a user is logged in then a JSON Web Token is sent to the server with every request.


The Fable compiler is used to compile the F# client code to JavaScript so that it can run in the browser.

Shared code between server and client

"Isomorphic F#" started a bit as a joke about Isomorphic JavaScript. The naming is really bad, but the idea to have the same code running on client and server is really interesting. If you look at src/Server/Shared/Domain.fs then you will see code that is shared between client and server. On the server it is compiled to .NET core and for the client the Fable compiler is translating it into JavaScript. This is a really convenient technique for a shared domain model.


Start the full build (incl. UI tests) with:

> build.cmd // on windows
$ ./build.sh // on unix


Expecto is a test framework like NUnit or xUnit, but much more developer friendly. With Expecto you write tests as values in normal code. Tests can be composed, reduced, filtered, repeated and passed as values, because they are values. This gives the programmer a lot of leverage when writing tests.

If you are in development mode then you can use Expecto's focused test feature to run a selected test against the running server.


canopy is a F# web automation and testing library, built on top of Selenium. In our expecto suite it looks like the following:

    testCase "login with test user" <| fun () ->
        url serverUrl
        waitForElement ".elmish-app"

        click "Login"

        "#username" << "test"
        "#password" << "test"

        click "Log In"

        waitForElement "Isaac Abraham"

Canopy in action

Additional tools


FAKE is a build automation system with capabilities which are similar to make and rake. It's used to automate the build, test and deployment process. Look into build.fsx for details.


Paket is a dependency manager and allows easier management of the NuGet packages.