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JavaScript without the Browser

2:22 with Andrew Chalkley

Node.js allows you to write JavaScript programs outside of the browser. In this video we get into the nuts and bolts behind it.

Native Objects

Native objects are those objects that are part of the JavaScript programming language and are available in both Node.js and the Browser.

Host Objects

Host objects are those objects that are only available in a single environment. For example the DOM, or Document Object Model is not available in Node.js but are available in the Browser. Likewise, the host objects to access the local file system is not available in the Browser but are in Node.js.

Now you've seen a simple example of a JavaScript program 0:00
running outside the browser. 0:03
Let's go into a little more detail about what's available to you, and 0:05
what's not when writing applications like this. 0:08
As developers, we use the JavaScript programming language that's interpreted 0:12
and executed by the browser's engine against browser specific APIs 0:17
like the DOM, or document object model. 0:22
When thinking about a JavaScript program in the browser, 0:25
you can split it up into two distinct parts. 0:28
Firstly, native objects. 0:31
These are the objects provided by the JavaScript programming language, 0:33
objects like string, array, date, math, and many more. 0:37
You can use these in any environment, not just in the browser. 0:41
Secondly, host objects. 0:45
These are the objects provided by the environment. 0:47
In the case of the browser, it's things like Window, document, history, XMLHttpRequest, 0:50
HTTP request and many more. 0:55
As JavaScript became more in demand, 0:57
the performance of the JavaScript engines became more important. 0:59
JavaScript started becoming a more viable option 1:03
to build not just browser applications, but all types of applications. 1:06
Chrome, Google's Internet browser, began dominating the performance benchmarks. 1:10
With its JavaScript engine V8 going open source, it became 1:15
the perfect environment for something new to appear, something to write any type of 1:19
general purpose application in JavaScript and that was Node.js. 1:24
Ryan Dahl ripped Chrome's V8 JavaScript engine out of the browser 1:29
leaving all the browser host objects behind, and provided new ones to allow for 1:33
the new types of applications to be written. 1:37
Objects like HTTP, HTTPS, fs for file system, URL, OS and much more. 1:40
The coupling of the V8 engine with the APIs is known as the Node.js or 1:47
the Node.js environment. 1:53
JavaScript applications are now free to run stand alone on a personal computer or 1:55
even on the Internet running on a server. 2:00
The key to writing any JavaScript application 2:03
is knowing what's available to you. 2:06
The native object should be available to you no matter what the environment. 2:08
They're there both in the browser and in Node.js. 2:12
However, in each environment you'll have access to their particular host objects 2:16
which can be completely different. 2:20

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