The url-join library for Node.js nicely combines URLs and was convenient, so I’d like to introduce it. By the way, it can also be used in browser JavaScript.

• GitHub: jfromaniello/url-join: Join all arguments together and normalize the resulting url.
• npm: url-join

How to use url-join

I’ll introduce sample code actually using url-join.

My impression after using it is that it’s nice how it properly considers / and URL query parameters ? & to combine URL strings.

Normal case

First, I tried it with a typical pattern. There seems to be no problem.

var urljoin = require('url-join');
urljoin('http://example.com', 'a', '/b/cd', '?foo=123');
// 'http://example.com/a/b/cd?foo=123'

Case with consecutive /

Even in cases like the following where / (slash) appears consecutively, url-join combines them nicely. It’s nice that it trims even if you accidentally have // consecutive.

var urljoin = require('url-join');
urljoin('http://example.com/', '/a', '//b/cd');
// 'http://example.com/a/b/cd'

Case where you want to add multiple URL query parameters

[OK] Just ?

For URL query parameter combination, it seems fine to just add ?.

var urljoin = require('url-join');
urljoin('http://example.com', 'a', '?foo=123', '?bar=456');
// 'http://example.com/a?foo=123&bar=456'

[NG] Just &

As expected, using just & didn’t work. It doesn’t care for this, so let’s use ?.

var urljoin = require('url-join');
urljoin('http://example.com', 'a', '&foo=123', '&bar=456');
// 'http://example.com/a&foo=123&bar=456'

That’s all from the Gemba that wants to combine URL parameters without worrying about details.