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How to Setup Grunt.js

2013-06-24 Grunt.js JavaScript

I have never really gotten into using Grunt, but once I got it going I found out how great it is at automating so many tasks like linting, testing and minifying my files. I actually came across it because I was trying to update one of my projects that had Grunt setup by someone else and so I tried to get it working locally. This led me to a lot of head scratching and confusion as apparently since version 0.4 of Grunt a few things had changed, however once I got everything working it was actually quite simple.

I was not able to find a simple concise guide on setting up Grunt as most of the information was quite scattered so I decided to write this little top to bottom guide. Grunt is actually a great tool and very easy to use. It will also save you lots of time fixing bugs and trying to manually do things like linting or minifying. I hope this guide will encourage you to setup Grunt for your project, so without further adieu.

Install Node.js

Grunt requires you to install nodejs to install Grunt itself and it’s plugins.

Download Node.js

Install Grunt

Now we can install grunt using the nodejs package manager.

$ npm install grunt --save-dev

To execute Grunt we’ll simply type grunt at the command line however if we’re using Windows we’ll need to type grunt.cmd. So for Windows also install the grunt-cli.

$ npm install -g grunt-cli

package.json

Your project will require a file called package.json which will contain some information Grunt will use when running tasks. The key part here is the dependencies section which makes it easy for anyone else working on your project to install the appropriate modules required for the project. Here is a sample from my js-url project.

{
  "name": "js-url",
  "version": "1.8.0",
  "description": "A simple, lightweight url parser for JavaScript.
  "main": "js-url.js",
  "repository": {
    "type": "git",
    "url": "https://github.com/websanova/js-url"
  },
  "author": {
    "name" : "Websanova"
  },
  "homepage" : "http://www.websanova.com",
  "license": "MIT, GPL",
  "dependencies": {
    "grunt-contrib-qunit": "",
    "grunt-contrib-uglify": "",
    "grunt-contrib-jshint": ""
  }
}

Installing Grunt Plugins

There may be some confusion about this as previously the modules were installed globally but as of version 0.4 of Grunt they are now installed on a per project basis. So with our dependencies set in the package.json file we can now easily install all our Grunt modules by simply running npm install from the project directory.

$ npm install

Note that you may get a warning here about package.json but don’t worry about that.

From here we can add or remove dependencies and I recommend looking at the Grunt plugins page for a full listing of plugins available along with instructions on how to use each one.

Ignoring Modules

Since you should now be using Grunt 0.4 the modules will be installed in the project directory. If you’re using any version control system like Git then we will need to ignore the node_modules folder and the npm-debug.txt file so that these don’t get committed as part of your project.

node_modules/
npm-debug.txt

Setting up a Gruntfile

The gruntfile.js is where you will setup how the plugins will work and which plugins to execute. When you run grunt.cmd it will automatically look for this file and run it accordingly. Note that in previous version this file may have simply been named grunt.js so a rename may be necessary. Below is a sample Grunt file that matches the package.json file above from my js-url project.

The key thing to note in the sample below is the loadNpmTasks which are your plugin names and should match your dependencies (if you plan to execute them). You will notice small configurations for each plugin. The best way to find out how to configure your plugins is to view the Grunt plugins page for detailed information on how to configure that plugin.

module.exports = function(grunt) {
  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    qunit: {
      files: ['index.html']
    },
    jshint: {
      options: {
        curly: true,
        eqeqeq: true,
        immed: true,
        latedef: true,
        newcap: true,
        noarg: true,
        sub: true,
        undef: true,
        boss: true,
        eqnull: true,
        globals: {
          'window': true,
          'jQuery': true
        }
      },
      files: {
        src: ['./js-url.js']
      }
    },
    uglify: {
      options: {
        banner: '/*! <%= pkg.name %> - v<%= pkg.version %> - <%= grunt.template.today("yyyy-mm-dd") %> */'
      },
      my_target: {
        files: {
          './js-url.min.js': ['./js-url.js']
        }
      }
    }
  });

  grunt.loadNpmTasks('grunt-contrib-qunit');
  grunt.loadNpmTasks('grunt-contrib-jshint');
  grunt.loadNpmTasks('grunt-contrib-uglify');

  grunt.registerTask('default', [ 'qunit', 'jshint', 'uglify' ]);
};