Express Basics

What we will answer

- What is happening when someone use the web? Or specifically, how do clients (browsers, lets say), servers and databased interact?
- What is an API?
	-  Lets looks at some using curl and postman, and then talk about how that relates to our servers.
- What is REST?
	- What is CRUD?
- How can we create a server using express?
- How do we create endpoints, like what we saw with other API's?
- How do we get info into out server from the client?
- What is middleware in express and how does it work?
- What is a static folder and how is this used in express?

To run the express server:

- First make sure you are in the "expressApp" directory.
- Next look at the package.json file. This will be where you should get into the habit of looking first.
	- This file will tell you what external dependencies are going to be downloaded in the next step.
	-  Additionally the `"scripts"` will be helpfull in how to run the app.
- Now, run ```npm i``` This can also be ran as ```npm install```
- At this point we can start the app (which will start the server). 
	- Run ```npm start```.
		- You may have noticed from the package.json file script for start that there is something called 'nodemon', this is an npm package (external dependency) that watches your file for a save and will re-run the server. Makes like easier when you are developing; not having to stop and start all the time manually.
- Visiting localhost:1337 in your browser at this point should reveal a message from the server.

Take away: - express - allowed us to create a really cool server to start making fullstack applications - API's - HTTP, with difference between the protocol and the module that node gives us. - Async code and how to handle it. - Promises - .then().catch() - async/await keywords -try and catch blocks of code