Create a function `generateUrl` to generate a URL from given parameters

generateURL.js

// exercise 2

const payload = {
  width: 360,
  height: 300,
  locale: 'en',
  toolbar_bg: '',
  interval: '3h',
  pair: 'BTC_USD',
}

let URL = "http://testurl.bitfinx.com/"

const getURL = (data) => {
    const params = Object.keys(data)
    	.filter(param => data[param])
      .map(key => `${key}=${data[key]}`)
      .join('&')
   return `${URL}?${params}`
}

console.log(getURL(payload))

// Excersie 3

const volumeSetup = () => {
	// I'm not sure if this part works at all, I'm assuming is part of the demo
	const volumeUnit = window.APP.util.getSettings('ticker_vol_unit').toUpperCase();
  	// Since we're using a patter convention maybe a more adaptble way would be to use the sufix as a identifier
	// Easier to read and maintain
	$(`#tickervolccy_${volumeUnit === 'FIRSTCCY' ? 0 : volumeUnit}`).prop("checked", true);
	// override currencies list
	var result = window.APP.util.initCurrenciesList()
	return result
}

2. Create a function generateUrl to generate a URL from given parameters:
   {
   width: 360,
   height: 300,
   locale: 'en',
   toolbar_bg: '',
   interval: '3h',
   pair: 'BTC_USD',
   }
   You can use any lib but the generated result should be
   "http://testurl.bitfinx.com/?height=300&interval=3h&locale=en&pair=BTC_USD&width=360"
   More parameters are planned to be added/removed later and the the result should neglect the empty params (ex: should not include toolbar_bg in URL when its value is empty).

3. Apply some refactoring to improve the code of the following function. Explain the reasons behind your changes and which benefit they bring into the code.

var volumeSetup = function () {
// setup volume unit interface
var volumeUnit = window.APP.util.getSettings('ticker_vol_unit').toUpperCase();
var element = null;
if (volumeUnit === 'FIRSTCCY') {
element = $('#tickervolccy_0');
} else if (volumeUnit === 'USD') {
element = $('#tickervolccy_USD');
} else if (volumeUnit === 'BTC') {
element = $('#tickervolccy_BTC');
} else if (volumeUnit === 'ETH') {
element = $('#tickervolccy_ETH');
}
if (element) {
element.prop("checked", true);
}
// override currencies list
var result = window.APP.util.initCurrenciesList()
return result
}