JAVASCRIPT

URLSearchParams(new URL(url).search)

// Retrieve params via url.search, passed into ctor
var url = new URL('https://example.com?foo=1&bar=2');
var params = new URLSearchParams(url.search);

// Pass in a string literal
var params2 = new URLSearchParams("foo=1&bar=2");
var params2a = new URLSearchParams("?foo=1&bar=2");

// Pass in a sequence of pairs
var params3 = new URLSearchParams([["foo", "1"], ["bar", "2"]]);

// Pass in a record
var params4 = new URLSearchParams({"foo": "1", "bar": "2"});

javascript urlsearchparams to string

let params = new URLSearchParams('foo=2'); // "location.search" to read from URL

params.append('bar', 4);                   //Add a bar parameter.
console.log(params.toString());            //Prints 'foo=2&bar=4'

location.search = params.toString();       // write changes to URL

URLSearchParams for query params

import React, { useEffect, useState } from "react";
import { useLocation } from "react-router-dom";

function CheckoutDetails() {
  const location = useLocation();
  const [amountValue, setAmountValue] = useState(1);

  // function to get query params using URLSearchParams
  useEffect(() => {
    const searchParams = new URLSearchParams(location.search);
    if (searchParams.has("amount")) {
      const amount = searchParams.get("amount");
      setAmountValue(parseInt(amount, 10));
    } else {
      setAmountValue(1);
    }
  }, [location]);

  return (
  	<p>Amount: {amountValue}</p>
  )
  

urlsearchparams array

function buildParams(data) {
    const params = new URLSearchParams()

    Object.entries(data).forEach(([key, value]) => {
        if (Array.isArray(value)) {
            value.forEach(value => params.append(key, value.toString()))
        } else {
            params.append(key, value.toString())
        }
    });

    return params.toString()
}