Friday, August 16, 2013

Automated JavaScript tasks with Grunt

I am currently working on a JavaScript only project and was looking for a way to automate some of the JavaScript processes. I was primarily looking for a way to get my tests automated, more or less the same as when you check-in code, your tests get automatically run.

For this I chose grunt, which can easily execute different tasks, not only can it automate your test runs, but it can also automate other JavaScript tasks, like minifying your files, running them through jslint, ... You can find a complete list on the grunt site.

The project I am working on is a Windows 8 application (not XAML this time, but JavaScript, HTML5, ...). So I am working in a .Net environment with a solution and a couple of projects.

Grunt Basics

To get started with grunt, first thing you will need to do is install node. All tasks you will be running in grunt will need to be installed using nodes packaging system npm (you can compare npm to the gem install process in ruby or nuget in .Net). After installing node, you can install grunt using npm. Once you've done this, you can start creating a grunt file in your web projects. A grunt file contains different tasks that need to be run, like uglify, jslint, minify, ...). You can find all info on getting started here.

Running jasmine tests with grunt

Now, the thing I wanted to be able to do, was run my jasmine tests though grunt. For this I have some simple jasmine tests set up. I could already run these through the jasmine browser runner. I also tried out a setup that ran my jasmine tests browserless through phantomjs and with the help of the build in Resharper runner, which works great. 

For running these same tests with the help of grunt I needed to install a couple of extra grunt tasks through npm: contrib-jasmine and contrib-connect. The first one, obviously is needed to run your jasmine tests. The second one, connect, can be used to set up a browserless environment for grunt, so it won't start up a browser session with every run of your grunt file. Connect can also be replaced by node itself.

The grunt file itself contains tasks for connect and jasmine:

module.exports = function (grunt) {

    // Project configuration.
        pkg: grunt.file.readJSON('package.json'),
        jasmine: {
            src: '<%= %>.Web/*.js',
            options: {
                vendor: ['<%= %>.Web/Scripts/*.js', '<%= %>.Web/lib/*.js'],
                host: '<%= connect.test.port %>/',
                specs: '<%= %>.Web/specs/*.js'
        connect: {
            test: {
                port: 8000,
                base: '.'


    // Default task(s).
    grunt.registerTask('default', ['connect', 'jasmine']);

You can see that in the jasmine task, I use the port number of my connect task. In my default task, at the bottom of the file, I first fire up the connect port and once that one is running, I let grunt run my jasmine tests.

Once I now issue the grunt command at the command line,I can see it running my tests.

One step further: automated build

Running my jasmine tests locally this way, is cool by itself, but it would be even nicer if I could integrate this in some sort of automated build process. Ie. check-in my code, trigger the grunt task runner, which will run my tests, run jslint, run uglify, ... Basically, get a finished product at the end of the pipeline. 

The project I am working on right now, I got it using tfsservice, since I wanted to find out what its' pro's and cons are. This means, for automating my build, I had to rely on msbuild to do the trick for me. Now, tfsservice has got iisnode installed on it, so it should be possible to have it run grunt tasks as well. 

To get this working, I altered some things in my grunt setup. First of all, I reinstalled grunt and all the packages it uses, so that they got saved locally into my project. This means reissuing the npm install command for grunt, contrib-jasmine, ... but WITH the --save-dev option. This will create a packages folder inside your project with all necessary files for each plugin saved locally inside your project. Once you commit your project to your source control system, all packages will also be present locally on the build server and don't need to be installed globally on your build server (something you just cannot do on tfsservice, being, that you're not sure on which build server you will be running next, which means reinstalling all packages with every run, which is just time consuming. You just don't want to do that.). 

I additionally installed the grunt-cli package locally (so, again, with the --save-dev option). Grunt-cli is the grunt command line interface. It gives you the grunt command locally (read: on your build server). 

Once you have done this, you can alter your csproj file of the project you want to use grunt in (remember: I am working in a .Net context here). For this, I added an additional target at the end of my csproj file: 

  <Target Name="RunGrunt">
    <Exec ContinueOnError="false" WorkingDirectory="$(MSBuildThisFileDirectory)\.." Command="./node_modules/.bin/grunt --no-color" />

This target uses my locally installed version of grunt. The --no-color option I added to get the grunt output nicely formatted. If you don't add this option, your output will look pretty messy.

You will also need to tell your build process to also run grunt after your build. So also add:

<Project ToolsVersion="4.0" DefaultTargets="Build;RunGrunt" xmlns="">

After these alterations, you will see your grunt output in the output window of Visual Studio after building your project. This should also make it possible to automatically run grunt on my tfsservice.

For this I made a build definition for my tfsservice. After checking in my code, the grunt task gets run as well, only, for now, it exits with errors (return fs.existsSync(filepath);
  TypeError: Object # has no method 'existsSync'). I looked in to these errors and apparently they are due to the fact that tfsservice doesn't use the latest version of node. I asked the tfs team if they could fix this and they promised me they'd get it done by the end of the month. So, for now, I'm still hoping to get this up and running in a couple of weeks. Normally, once node gets upgraded, there shouldn't be a problem. 


  1. Thank you for the excellent article. I'm doing a similar .NET project but am getting the following error: The command "./node_modules/.bin/grunt --no-color" exited with code 9009. Is this something you've seen at all?

  2. Hi victor,

    Didn't get this same error, no, but, it might have something to do with the path to grunt you're using in Visual Studio. For this, see the following Q's and answers on stackoverflow: and

    Hope this helps.

  3. We have a build server, where we cannot install node or grunt, the install has to occur as a part of build. any ideas on how to achieve it?

  4. Naunihal Sidhu - install the Nuget package for Grunt