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What is Node.js

5:48 with Reggie Williams

In this step, we'll learn about how Node.js lets us write JavaScript programs that work without the browser.

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[MUSIC] 0:00

Hi, I'm Reggie, and I'm an instructor at Treehouse. 0:09

My pronouns are he, him. 0:12

Today we'll learn about the Node.js, JavaScript runtime environment. 0:14

A runtime environment is where code is executed. 0:19

Runtime environments like Node provide access to features of 0:23

the JavaScript language like data types, objects, and functions. 0:26

Plus, they have a built in engine that compiles code, 0:31

translating your code into something that computers can use and understand. 0:34

We often run JavaScript code in a web browser. 0:39

Browsers like Chrome are one example of a runtime environment. 0:43

Browser runtimes can be called front end runtimes. 0:47

While the browser is one of the most common JavaScript runtime environments, 0:51

there are other non browser environments Node.js being the most popular. 0:55

Instead of using the browser, Node is used for backend, or server-side JavaScript. 1:00

Dynamic web applications can be thought of as restaurants. 1:07

While web applications have a browser client for users to interpret and 1:10

interact with, restaurants have a menu for guests to understand their offerings and 1:14

make orders. 1:18

Servers, and I mean restaurant servers, take the guests order, 1:20

pass it to the kitchen, and return with the food. 1:25

We can think of a server in this example as an application programming interface, 1:30

or a way for programs to communicate. 1:34

The kitchen in this example, is the back end of the application. 1:38

They take a request from a client and return the requested resources or food. 1:42

Backend JavaScript is often used to manage data or interact with other applications. 1:48

Node can be used both to make front end applications dynamic, 1:53

and it can be used on its own. 1:57

Before Node developers had to use other languages like Python to manage data, 2:00

authenticate users, and deliver personalized experiences. 2:05

All JavaScript runtime environments use the standard built in objects that 2:09

are part of the JavaScript programming language. 2:13

These are called native objects, and are often referred to as global objects. 2:17

Different runtime environments have unique objects that allow JavaScript code to 2:23

execute in that specific environment. 2:27

These are called host objects, and they're supplied to JavaScript by the environment. 2:31

They're only available in that environment. 2:36

The browser, for example, provide the window object for accessing the DOM. 2:39

This allows us to manipulate the page using JavaScript. 2:45

Node.js provides a different set of host objects. 2:48

For example, host objects like protocols for requesting data, reading files, 2:52

and others are available to JavaScript to allow it to run outside of the browser. 2:57

Throughout the course, you'll learn more about some of Node's host objects and 3:03

how to use them in your programs. 3:07

Node is based on Google Chrome's V8 open source JavaScript engine, and 3:09

it comes equipped with its own tools. 3:13

The V8 engine is what compiles JavaScript and handles memory. 3:17

A main benefit of Node is its non blocking, 3:21

asynchronous execution of JavaScript code. 3:24

In other words, it can begin executing multiple operations at once without 3:28

waiting for one process to complete before moving on to the next. 3:32

To better explain, I'll use my favorite kind of example, one about food. 3:37

Think of the Node environment and 3:42

its JavaScript engine as the kitchen of your favorite restaurant. 3:44

A busy kitchen accepts many food orders, often at the same time. 3:48

The kitchen uses its resources or 3:53

ingredients to prepare each order and deliver it to the customer. 3:55

A typical restaurant kitchen can receive an order from one customer and 3:59

start it while accepting another. 4:03

They can begin work on one task, 4:06

then another without being blocked by other tasks. 4:08

This non blocking activity makes the process of preparing food orders faster 4:12

and more efficient. 4:17

Imagine if the restaurant kitchen only accepted one order at a time and 4:19

couldn't start another order until the last was finished. 4:22

Being blocked by task after task would likely result in long wait times and 4:26

bad reviews. 4:32

Similar to a fast and efficient restaurant kitchen, 4:33

the Node runtime environment can handle multiple tasks at the same time. 4:36

Nodes non-blocking capabilities allow developers to build real time, 4:41

multi-user apps that handle many users, events, and data requests at once. 4:47

Because of these capabilities, Node apps can easily scale or 4:54

be built to serve more people. 4:58

Netflix uses Node to stream videos to millions of users. 5:01

Companies like PayPal and Capital One have increased the speed of their 5:05

transactions when they went from Java to Node. 5:09

To accommodate millions of job seekers, 5:12

LinkedIn mobile platform is built with Node.js. 5:15

NASA even uses Node to reduce the time it takes to gather information from 5:18

spacesuits. 5:23

In this course, 5:24

we will build two command line applications to get familiar with Node.js. 5:25

One to retrieve Treehouse student profile information, and one to search for 5:29

dictionary definitions. 5:34

Each app will retrieve information from the web and print it to the console. 5:36

These apps will help you get acquainted with some of the features of Node and 5:41

find out why you might want to use it in your projects. 5:44

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