Gruntfile.js

module.exports = function(grunt) {

    // load all grunt tasks matching the ['grunt-*', '@*/grunt-*'] patterns
        require('load-grunt-tasks')(grunt);
        require('time-grunt')(grunt);

    // 1. All configuration goes here
    grunt.initConfig({
        pkg: grunt.file.readJSON('package.json'),

        jekyll: {
            serve: {
               options: {
                    serve: true,
                    dest: '_site',
                    config: '_config-dev.yml',
                    watch: true
                }
            },
            build: {
                options: {
                    dest: '_site',
                    config: '_config-dev.yml'
                }
            },
            production: {
                options: {
                    dest: '_site',
                }
            }
        },

        browserSync: {
            files: {
                src: ['_site/css/*.css', '_site/*.html']
            },
            proxy: 'localhost:4000'
        },

        uglify: {
          global: {
            files: {
              "js/scripts.min.js": ["js/scripts.js"],
              "js/vendor.min.js": ["js/vendor/*.js"]
            }
          }
        },
        imagemin: {
          dynamic: {
            files: [{
              expand: true,
              cwd: 'images/',
              src: ['**/*.{png,jpg,gif,svg}'],
              dest: 'images/'
            }]
          }
        },
        sass: {
          global: {
            options: {
              style: "compressed"
            },
            files: {
              "css/main-unprefixed.css": "scss/main.scss"
            }
          }
        },
        autoprefixer: {
           dist: {
               files: {
                   'css/main.css': 'css/main-unprefixed.css'
               }
           }
       },
        critical: {
            dist: {
                options: {
                  base: './',
                  dimensions: [{
                    width: 1300,
                    height: 900
                   },
                   {
                    width: 500,
                    height: 900
                  }]
                },
                files: [
                  {src: ['_site/index.html'], dest: '_includes/critical-home.css'},
                  {src: ['_site/about.html'], dest: '_includes/critical-about.css'},
                  {src: ['_site/work.html'], dest: '_includes/critical-work.css'},
                  {src: ['_site/articles.html'], dest: '_includes/critical-articles.css'},
                ]
            }
        },
       watch: {
         html: {
            files: "*.html",
            tasks: ["jekyll:build"]
         },
         js: {
           files: ["js/*.js", "!js/scripts.min.js", "!js/vendor.min.js"],
           tasks: ["uglify"]
         },
         css: {
           files: ["scss/*.scss"],
           tasks: ["sass", "autoprefixer"]
         }
       },
       concurrent: {
           dev: ['jekyll:serve', 'browserSync', 'watch'],
           options: {
               logConcurrentOutput: true
           }
       }
    });


    // 4. Where we tell Grunt what to do when we type "grunt" into the terminal.
    grunt.registerTask("default", ["concurrent:dev"]);
    grunt.registerTask("production", ["jekyll:production"]);

};