1-node-npm-yarn-package-json

1 - Node, NPM, Yarn, and package.json

In this section we will set up Node, NPM, Yarn, and a basic package.json file.

First, we need to install Node, which is not only used for back-end JavaScript, but all the tools we need to build a modern Front-End stack.

Head to the download page for macOS or Windows binaries, or the package manager installations page for Linux distributions.

For instance, on Ubuntu / Debian, you would run the following commands to install Node:

curl -sL https://deb.nodesource.com/setup_6.x | sudo -E bash -
sudo apt-get install -y nodejs

You want any version of Node > 6.5.0.

npm, the default package manager for Node, comes automatically with Node, so you don't have to install it yourself.

Note: If Node is already installed, install nvm (Node Version Manager), make nvm install and use the latest version of Node for you.

Yarn is another package manager which is much faster than NPM, has offline support, and fetches dependencies more predictably. Since it came out in October 2016, it received a very quick adoption and is becoming the new package manager of choice of the JavaScript community. We are going to use Yarn in this tutorial. If you want to stick to NPM you can simply replace all yarn add and yarn add --dev commands of this tutorial by npm install --save and npm install --dev.

• Install Yarn by following the instructions. You can likely install it with npm install -g yarn or sudo npm install -g yarn (yeah, we're using NPM to install Yarn, much like you would use Internet Explorer or Safari to install Chrome!).

• Create a new folder to work in, and cd in it.

• Run yarn init and answer the questions (yarn init -y to skip all questions), to generate a package.json file automatically.

• Create an index.js file containing console.log('Hello world').

• Run node . in this folder (index.js is the default file Node looks for in the current folder). It should print "Hello world".

Running node . to execute our program is a bit too low-level. We are going to use an NPM/Yarn script to trigger the execution of that code instead. That will give us a nice abstraction to be able to always use yarn start, even when our program gets more complicated.

• In package.json, add a scripts object to the root object like so:

"scripts": {
  "start": "node ."
}

package.json must be a valid JSON file, which means that you cannot have trailing commas. So be careful when editing manually your package.json file.

• Run yarn start. It should print Hello world.

• Create a .gitignore file and add the following to it:

npm-debug.log
yarn-error.log

Note: If you take a look at the package.json files I provide, you will see a tutorial-test script in every chapter. Those scripts let me test that the chapter works fine when running yarn && yarn start. You can delete them in your own projects.

Next section: 2 - Installing and using a package

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