Every application has to be set up, so we'll begin with that. Create a folder for your project—I'll call mine simpleBlog—and inside that, create a file named package.json. If you've used Node.js before, you know that the package.json file describes the project; lists the project home page, repository, and other links; and (most importantly for us) outlines the dependencies for the application.

Here's what the package.json file looks like:

{
  "name": "simple-blog",
  "description": "This is a simple blog.",
  "version": "0.1.0",
  "scripts": {
    "start": "nodemon server.js"
  },
  "dependencies": {
    "express": "3.x.x",
    "ejs"    : "~0.8.4",
    "bourne" : "0.3"
  },
  "devDependencies": {
    "nodemon": "latest"
  }
}

This is a pretty bare-bones package.json file, but it has all the important bits. The name, description, and version properties should be self-explanatory. The dependencies object lists all the npm packages that this project needs to run: the key is the name of the package and the value is the version. Since we're building an ExpressJS backend, we'll need the express package. The ejs package is for our server-side templates and bourne is our database (more on this one later).

The devDependencies property is similar to the dependencies property, except that these packages are only required for someone working on the project. They aren't required to just use the project. For example, a build tool and its components, such as Grunt, would be development dependencies. We want to use a package called nodemon. This package is really handy when building a Node.js backend: we can have a command line that runs the nodemon server.js command in the background while we edit server.js in our editor. The nodemon package will restart the server whenever we save changes to the file. The only problem with this is that we can't actually run the nodemon server.js command on the command line, because we're going to install nodemon as a local package and not a global process. This is where the scripts property in our package.json file comes in: we can write simple script, almost like a command-line alias, to start nodemon for us. As you can see, we're creating a script called start, and it runs nodemon server.js. On the command line, we can run npm start; npm knows where to find the nodemon binary and can start it for us.

So, now that we have a package.json file, we can install the dependencies we've just listed. On the command line, change to the current directory to the project directory, and run the following command:

npm install

You'll see that all the necessary packages will be installed. Now we're ready to begin writing the code.