Hello Express

This is a simple example app using the Express web framework for Node.js. Used to demo Node, Yarn, Express, etc. for a friend.

I basically just annotated the example from the official docs with some comments, and expanded the javascript syntax to be more obvious.

Other files in this repo:

package.json is a file at the root of every project that uses Node. It has some information about the project (the package), including the other packages it depends on. I used the yarn package manager to generate the file with yarn init. Then I installed express as the only dependency by running yarn add express.
node_modules is a directory managed by Yarn. It contains a local copy of our project's dependencies (Express) and their dependencies. So if you have multiple packages that rely on Express, you don't need to worry about keeping their versions in sync. Each uses its own copy of Express from its own node_modules directory.
- node_modules is not checked into version control—it's listed in the .gitignore file. When you check out a Node project from a git remote, you have to run yarn install to download local copies of all your dependencies to node_modules.
  - package.json is checked into version control and it's how Yarn knows what to download into node_modules.
yarn.lock is another file managed by Yarn. It complements package.json and you pretty much never have to look at it.

TLDR