Why doesn't Node.js have a native DOM?

Question

When I discovered that Node.js was built using the V8 JavaScript engine, I thought:

Great, web scraping will be easier as the page

Answer 1

Node is a runtime environment, it does not render a DOM like a browser.

Answer 2

Because there isn't a DOM. DOM stands for Document Object Model. There is no document in Node, so not DOM to manipulate it. That is definitively a browser thing.

You can use a library like cheerio though which gives you some simple DOM manipulation.

Node is server-level JavaScript. It's just the language applied to a basic system API, more like C++ or Java.

Answer 3

Javascript != browser. Javascript as a language is not tied to browsers; node.js is simply an implementation of Javascript that is intended for servers, not browsers. Hence no DOM.

Answer 4

It seems people have answered 'why' but not how. A quick answer of how is that in a web browser, a document object is exposed (hence DOM , document object model). On windows this object is called document object. You can refer to this page and look at the methods it exposes which are for handling HTML documents like createElement. I don't use node.js or haven't done COM programming in a while but I'd imagine you could use DOM in node.js by simply calling the COM object IHTMLDocument3. Of course for other platforms like Mac OS X or Linux you would probably have to use something from their OS api. This should allow you to easily build a webpage server side using DOM, or to scrape incoming web pages.

Answer 5

If you read DOM as 'linked objects immediately accessible from my script' then the answer 'it does, but it's very different from set of objects available from web document script'. The main reason is that node is 'evented I/O for V8', not 'HTML tree objects for V8'

Answer 6

2018 answer: mainly for historical reasons, but this may change in future.

Historically, very little DOM manipulation was done on the server. Addiotinally, as other answers allude, the JS stdlib and the DOM are seperate libraries - if you're using node, for, say, Unix scripting, then HTMLElement and NodeList etc aren't really relevant to that.

However: server-side DOM manipulation is now a very common part of delivering web apps. Web servers need to understand the structure of pages, and, if asked to render a resource as HTML, deliver HTML content that reflects the initial state of a web application. This means web apps load much faster than if the server simply delivers a stub page and has the browsers then do the work of filling in the real content. Currently this is done with JSDom and similar, but in the same way node has Request and Response objects built in, having DOM functions maintained as part of the stdlib would help with this task.