How to extract the host from a URL in JavaScript?

javascript node.js parsing url

44,255

Solution 1

If you actually have valid URLs, this will work:

var urls = [
    'http://example.com:3000',
    'http://example.com?pass=gas',
    'http://example.com/',
    'http://example.com'
];

for (x in urls) {
    var a = document.createElement('a');
    a.href = urls[x];
    console.log(a.hostname);
}

//=> example.com
//=> example.com
//=> example.com
//=> example.com

Note, using regex for this kind of thing is silly when the language you're using has other built-in methods.

Other properties available on A elements.

var a = document.createElement('a');
a.href = "http://example.com:3000/path/to/something?query=string#fragment"

a.protocol   //=> http:
a.hostname   //=> example.com
a.port       //=> 3000
a.pathname   //=> /path/to/something
a.search     //=> ?query=string
a.hash       //=> #fragment
a.host       //=> example.com:3000

EDIT #2

Upon further consideration, I looked into the Node.js docs and found this little gem: url#parse

The code above can be rewritten as:

var url = require('url');

var urls = [
    'http://example.com:3000',
    'http://example.com?pass=gas',
    'http://example.com/',
    'http://example.com'
];

for (x in urls) {
    console.log(url.parse(urls[x]).hostname);
}

//=> example.com
//=> example.com
//=> example.com
//=> example.com

EDIT #1

See the revision history of this post if you'd like to see how to solve this problem using jsdom and nodejs

Solution 2

Since you're using node, just use the built-in url.parse() method; you want the resulting hostname property:

var url=require('url');
var urls = [
  'http://example.com:3000',
  'http://example.com?pass=gas',
  'http://example.com/',
  'http://example.com'
];

urls.forEach(function(x) {
  console.log(url.parse(x).hostname);
});

Solution 3

A new challenger has appeared. According to node docs, you can also use

   var url = new URL(urlString);
   console.log(url.hostname);

https://nodejs.org/api/url.html#url_the_whatwg_url_api

This seems to be a more current way.

Solution 4

I'm using Node ^10 and this is how I extract the hostname from a URL.

var url = URL.parse('https://stackoverflow.com/q/13506460/2535178')
console.log(url.hostname)
//=> stackoverflow.com

View more solutions

44,255

ThomasReggi

Updated on July 09, 2022

Comments

ThomasReggi almost 2 years
Capture the domain till the ending characters $, \?, /, :. I need a regex that captures domian.com in all of these.
```
domain.com:3000
domain.com?pass=gas
domain.com/
domain.com
```
- ThomasReggi over 11 years
  
  @macek I built a URL / URI builder for javascript that takes arguments and constructs the URL from an object. I'm looking to create a regular expression that can take a string and create the object. stackoverflow.com/questions/13498417/build-urls-from-json
- ThomasReggi over 11 years
  
  Published my module here github.com/reggi/schemejs
ThomasReggi over 11 years

javascript but I would really just like a regex
ThomasReggi over 11 years

This would be great, but I'm working server-side. No doc =[. Might be a way to fake it.
maček over 11 years

Have you heard of jsdom? Also, you should've mentioned you were using something like node.js in the tags :P
ThomasReggi over 11 years

I'm on it. Yes. It's late, Tags are gooooood. Thanks.
maček over 11 years

@ThomasReggi, I added a node.js example. I hope this helps you.
maček over 11 years

PHP was ported to JS? that's a scary, scary thought.
ThomasReggi over 11 years

returns { pathname: '0', path: '0', href: '0' } { pathname: '1', path: '1', href: '1' } { pathname: '2', path: '2', href: '2' } { pathname: '3', path: '3', href: '3' }
maček over 11 years

@ThomasReggi, I discovered that nodejs has it's own url#parse method. Please see Edit #2 above.
ebohlman over 11 years

Goofed-up test harness (copied from another answer), updated in my answer. Lesson: don't use for (...in...) to iterate over arrays.
cprcrack almost 10 years

+1 for nodejs.org/api/…
xShirase almost 10 years

Does not work : s="stackoverflow.com/questions/13506460/…" s.match(/^((?:[a-z0-9-]+\.)*[a-z0-9-]+\.?)(?::([0-9]+))?(.*)‌$/i) gives the following result : ["stackoverflow.com/questions/13506460/…", "http", undefined, "://stackoverflow.com/questions/13506460/how-to-extract-the-‌host-from-a-url-in-j‌avascript"]
stroncium almost 10 years

Don't post fake test please. Your results contain string "http" as a matched string while the string you say you run regexp on doesn't contain "http" substring. You either patched the execution result or source code of your jS virtual machine to achieve this results. "stackoverflow.com/questions/13506460/how-to-extract...".mat‌ch(/^((?:[a-z0-9-]+\‌.)*[a-z0-9-]+\.?)(?:‌:([0-9]+))?(.*)$/i) works perfectly fine resulting in ["stackoverflow.com/questions/13506460/how-to-extract...", "stackoverflow.com", undefined, "/questions/13506460/how-to-extract..."]
stroncium almost 10 years

Using DOM objects is not JS feature, but DOM binding feature. DOM doesn't exist in many JS environments. Also, it is very slow, and the proper way to perform simple string parsing is EXACTLY using regexps.
xShirase almost 10 years

nope, stackoverflow auto cuts the url... Now, please check this fiddle : jsfiddle.net/WLGmv and let me know if I'm doing anything wrong.
stroncium almost 10 years

Sure thing. You try to use this regexp for the wrong purpose. If you reread the original question, it was not supposed to do what you want. You need to parse URLs with URI scheme, try this: /^(?:https?:\/\/)?((?:[a-z0-9-_]+\.)*[a-z0-9-_]+\.?)(?::([0-‌9]+))?(.*)$/i (works only for http and https or no URI scheme at all). Fiddle is here: jsfiddle.net/WLGmv/1
UpTheCreek about 9 years

Edit 2 will currently output all the properties of the parsed url, not just the hostname. You need to target the .hostname property.
Muhammad Umer over 6 years

it includes subdomain
Muhammad Umer over 6 years

hostname includes subdomain