https://circolab.eu/js/urlparam.js

1function getAllUrlParams(url) {
2	let queryString = url ? url.split('?')[1] : window.location.search.slice(1);
3	const obj = {};
4	if (queryString) {
5		// stuff after # is not part of query string, so get rid of it
6		queryString = queryString.split('#')[0];
7		// split our query string into its component parts
8		const arr = queryString.split('&');
9		for (let i = 0; i < arr.length; i++) {
10			// separate the keys and the values
11			const a = arr[i].split('=');
12			// set parameter name and value (use 'true' if empty)
13			let paramName = a[0];
14			let paramValue = typeof a[1] === 'undefined' ? true : a[1];
15			// (optional) keep case consistent
16			paramName = paramName.toLowerCase();
17			if (typeof paramValue === 'string') paramValue = paramValue.toLowerCase();
18			// if the paramName ends with square brackets, e.g. colors[] or colors[2]
19			if (paramName.match(/\[(\d+)?\]$/)) {
20				// create key if it doesn't exist
21				const key = paramName.replace(/\[(\d+)?\]/, '');
22				if (!obj[key]) obj[key] = [];
23				// if it's an indexed array e.g. colors[2]
24				if (paramName.match(/\[\d+\]$/)) {
25					// get the index value and add the entry at the appropriate position
26					const index = /\[(\d+)\]/.exec(paramName)[1];
27					obj[key][index] = paramValue;
28				} else {
29					// otherwise add the value to the end of the array
30					obj[key].push(paramValue);
31				}
32			} else {
33				// we're dealing with a string
34				if (!obj[paramName]) {
35					// if it doesn't exist, create property
36					obj[paramName] = paramValue;
37				} else if (obj[paramName] && typeof obj[paramName] === 'string') {
38					// if property does exist and it's a string, convert it to an array
39					obj[paramName] = [obj[paramName]];
40					obj[paramName].push(paramValue);
41				} else {
42					// otherwise add the property
43					obj[paramName].push(paramValue);
44				}
45			}
46		}
47	}
48
49	return obj;
50}