Now Node provides a great way to implement a build process with only npm.

1. We need to watch the versions of each sub modules which we are using. If anything gets updated or removed we have to look for another one to achieve the same. But here with npm, no such problem will come.
2. Adding new tasks into build tool will increase dependencies. But here we can use normal command prompt command like '&&' to combine multiple tasks.
3. Custom script file like (Gruntfile.js) for tasks. Here only package.json file is enough.
4. Doesn't support any commands which we use in command prompt. Here you can use all commands into your package.json file.

1. Default scripts
2. Custom scripts

1. Create an empty directory and initialize it as npm using npm init. It will ask you to construct your package.json file. If you feel lazy like me to hit enter many times, then go with shorthand script npm init --yes.
2. Now check your directory, a package.json file gets created like this :

{
  "name": "your_directory_name",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

1. By default, a test script will get created inside the script object. Inside the script object, we are going to configure our tasks.
2. Run the default task using npm test shorthand for npm run test

1. Let's install dev-dependencies first :

$ npm i -D jshint lite-server mocha concurrently node-sass uglify-js

1. Let's start creating our scripts :

"scripts": {
  ...
  "dev": "lite-server"
}

  "scripts": {
    ...
    "db": "json-server --watch db.json --port 3005"
  }  

  "scripts": {
    ...
    "start": "concurrently -k \"npm run dev\" \"npm run db\""
  }  

  "scripts": {
   ...
   "uglify": "mkdir -p dist/js && uglifyjs src/js/*.js -m -o dist/js/app.js"
  }  

  "scripts": {
    ...
    "lint": "jshint src/**.js"
  }  

"scripts": {
  ...
  "sass": "node-sass --include-path scss scss/main.scss assets/main.css"
}

"scripts": {
  ...
  "test": "mocha test"
}

"scripts": {
  ...
  "bash": "Location of the Bash/Shell script file"
}

"scripts": {

  "start": "concurrently -k \"npm run dev\" \"npm run watch-css\"",

  "dev": "lite-server",
  "db": "json-server --watch db.json --port 3005",

  "build-js": "mkdir -p dist/js && uglifyjs src/js/*.js -m -o dist/js/app.js",

  "lint": "lint jshint src/**/**.js",

  "build-css": "node-sass --include-path scss scss/main.scss assets/main.css",
  "watch-css": "nodemon -e scss -x \"npm run build-css\"",

  "test": "mocha test",
  "pretest": "npm run lint",
  "posttest": "echo the test has been run!",

  "bash": "Location of the bash/shell script file"
}

1. npm run dev- Bootstraps our app, opens it in the browser, reloads the browser whenever we make changes in source.
2. build-js- Minifies all our JavaScript files, which will be needed during production.
3. watch-css- Nodemon is a utility that will monitor for any changes in your source and automatically restart your server. Here I have used it to monitor for any changes in the .scss file, if there are changes, it will restart the server and build our css.

"scripts": {
  "test": "echo I am test",
  "pretest": "echo I run before test",
  "posttest": "echo I run after test"
}

1. npm test- It wraps the above three commands "pretest test posttest" and executes them in the order I have listed. Initially when you hit npm test it will look for pretest command. If it is there, it gets executed first, followed by test and then posttest. During the look up if it doesn't find pretest command it will directly execute the test command.