Question: I'm into some web scraping with Node.js. I'd like to use XPath as I can generate it semi-automatically with several sorts of GUI. The problem is that I cannot find a way to do this effectively.

1. `jsdom` is extremely slow. It's parsing 500KiB file in a minute or so with full CPU load and a heavy memory footprint.
2. Popular libraries for HTML parsing (e.g. `cheerio`) neither support XPath, nor expose W3C-compliant DOM.
3. Effective HTML parsing is, obviously, implemented in WebKit, so using `phantom` or `casper` would be an option, but those require to be running in a special way, not just `node <script>`. I cannot rely on the risk implied by this change. For example, it's much more difficult to find how to run `node-inspector` with `phantom`.
4. `Spooky` is an option, but it's [buggy enough](https://github.com/WaterfallEngineering/SpookyJS/issues/71), so that it didn't run at all on my machine.

What's the right way to parse an HTML page with XPath then?

Answer: 
You can do so in several steps.

1. Parse HTML with `parse5`. The bad part is that the result is not DOM. Though it's fast enough and W3C-compiant.
2. Serialize it to XHTML with `xmlserializer` that accepts DOM-like structures of `parse5` as input.
3. Parse that XHTML again with `xmldom`. Now you finally have that DOM.
4. The `xpath` library builds upon `xmldom`, allowing you to run XPath queries. Be aware that XHTML has its own namespace, and queries like `//a` won't work.

Finally you get something like this.

```
const fs = require('mz/fs');
const xpath = require('xpath');
const parse5 = require('parse5');
const xmlser = require('xmlserializer');
const dom = require('xmldom').DOMParser;

(async () => {
    const html = await fs.readFile('./test.htm');
    const document = parse5.parse(html.toString());
    const xhtml = xmlser.serializeToString(document);
    const doc = new dom().parseFromString(xhtml);
    const select = xpath.useNamespaces({"x": "http://www.w3.org/1999/xhtml"});
    const nodes = select("//x:a/@href", doc);
    console.log(nodes);
})();

```

Note that you have to prepend every single HTML element of a query with the `x:` prefix, for example to match an `a` inside a `div` you would need:

```
//x:div/x:a

```
I have just started using [`npm install htmlstrip-native`](https://github.com/zaro/node-htmlstrip-native) which uses a [native implementation](https://github.com/zaro/node-htmlstrip-native/blob/master/htmlstrip.cpp) to parse and extract the relevant html parts. It is claiming to be 50 times faster than the pure js implementation (I have not verified that claim).

Depending on your needs you can use html-strip directly, or lift the code and bindings to make you own C++ used internally in htmlstrip-native

If you want to use xpath, then use the wrapper already avaialble here;
 <https://www.npmjs.org/package/xpath>