JavaScript: How to get first parameter, actually first key from URL?

Question

I am trying to get first key from URL, like this:

const currentUrl = window.location.href; 
const parmsFromUrl = new URLSearchParams(currentUrl);
const paramToCheck = parmsFromUrl.keys[0];

But constantly I get undefined, can someone tell how me how to get only first parameter, not a value, I just want key? Thanks.

Answer 1

With URLSearchParams you have to use window.location.search

With URL you have to use window.location.href

const currentUrl = window.location.search;
const parmsFromUrl = new URLSearchParams(currentUrl);

URLSearchParams.keys() returns an iterator, so you have to use next() to get first value

const paramToCheck = parmsFromUrl.keys().next().value;