Basic Gruntfile with Concat

gruntfile.js

module.exports = function(grunt) {

  // Project configuration.
  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'), //<---imports the JSON metadata stored in package.json
    concat:{
      dist: {
        src: [
            'js/libs/*.js', // Selects all JS in the libs folder
            'js/main.js'  
        ],
        dest: 'js/build/production.js', //Output file after concatenating js files
      }
    }
  });

  // Load the plugin that provides the "concat" task.
  grunt.loadNpmTasks('grunt-contrib-concat');

  // Default task(s).
  grunt.registerTask('default', ['concat']); //<--- adds "concat" to the default task

};