Task automation with Grunt

Grunt is a task runner and a great way to automate your node projects. Let's add a simple grunt script to our project in order to automate running tests and code coverage. Let's install Grunt and Grunt CLI:

npm install -g grunt-cli
npm install grunt –-save-dev

The grunt-cafe-mocha is a grunt module for running mocha; this module will also allow us to automate code coverage reports:

npm install grunt-cafe-mocha –-save-dev

The grunt-jscoverage simply generates an instrumented version of our source code and writes it to ./lib-cov:

npm install grunt-jscoverage –-save-dev


The grunt-env allows you to set the current node environment, NODE_ENV:

npm install grunt-env  –-save-dev

Let's create a grunt file ./gruntfile.js. We load the grunt modules we just installed, and grunt.initConfig contains a configuration for each grunt module:

module.exports = function(grunt) {
  grunt.loadNpmTasks('grunt-jscoverage');
  grunt.loadNpmTasks('grunt-cafe-mocha');
  grunt.loadNpmTasks('grunt-env');

  grunt.initConfig({
    env: {
      test: { NODE_ENV: 'TEST' },
      coverage: { NODE_ENV: 'COVERAGE' }
    },
    cafemocha: {
      test: {
        src: 'test/*.js',
        options: {
          ui: 'bdd',
          reporter: 'spec',
        },
    },
    coverage: {
      src: 'test/*.js',
      options: {
        ui: 'bdd',
        reporter: 'html-cov',
        coverage: {
          output: 'coverage.html'
        }
      }
    },
  },
  jscoverage: {
    options: {
      inputDirectory: 'lib',
      outputDirectory: 'lib-cov',
      highlight: false
    }
  }
  });
  grunt.registerTask('test', [ 'env:test', 'cafemocha:test' ]);
  grunt.registerTask('coverage', [ 'env:coverage', 'jscoverage', 'cafemocha:coverage' ]);
};

The configuration for cafemocha contains two sections; one for running our tests and one for generating a code coverage report. In order to run our tests from grunt, execute the following command:

grunt test  

The following line registers a task that sets the environment using env and runs both the jscoverage and cafemocha:coverage tasks in sequence:

grunt.registerTask('coverage', [ 'env:coverage', 'jscoverage', 'cafemocha:coverage' ]);

In order to run our coverage from grunt, execute the following command:

grunt coverage

This command will generate the coverage report as described earlier.