Sometimes, we want to test if a URL string is absolute or relative with JavaScript.
In this article, we’ll look at how to test if a URL string is absolute or relative with JavaScript.
How to test if a URL string is absolute or relative with JavaScript?
To test if a URL string is absolute or relative with JavaScript, we use a regex.
For instance, we write
const r = new RegExp("^(?:[a-z]+:)?//", "i");
const isUrl = r.test("http://example.com");
to create a regex with the RegExp constructor.
We use ^(?:[a-z]+:)?// to check for the protocol part of the URL in our string.
And use i to check the string in a case insensitive manner.
Then we call r.test to check "http://example.com" is an absolute URL.
Conclusion
To test if a URL string is absolute or relative with JavaScript, we use a regex.
