Currency Converter for Dynamic Pages

(() => {
const DECIMAL_DIGITS = 2;
let elements = document.querySelectorAll(this.selector);
if (!elements.length) return;
const userLocation = window.twik_user_data.location;
const currencies = {
'$': userLocation.usd_exchange_rate,
'€': userLocation.eur_exchange_rate,
'₪': userLocation.nis_exchange_rate,
'£': userLocation.gbp_exchange_rate
};
const symbols = Object.keys(currencies).reduce((acc, val) => acc + (acc ? ',' : '') + val, '');
const regex = RegExp('[' + symbols + ']');
Array.from(elements).forEach(element => {
let symbol;
const nodes = Array.from(element.querySelectorAll('*')).concat(element);
const loop = replacer => {
nodes.forEach(el => {
Array.from(el.childNodes).forEach(node => node.nodeType === node.TEXT_NODE && replacer(node))
});
};
loop(node => {
if (!symbol) {
let match = node.nodeValue.match(regex);
symbol = match && match[0];
}
});
if (!symbol || !currencies[symbol] || symbol === userLocation.currency_symbol) return;
loop(node => {
node.nodeValue = node.nodeValue.replace(regex, userLocation.currency_symbol);
if (/\d/.test(node.nodeValue)) {
node.nodeValue = node.nodeValue
.replace(',', '')
.trim()
.replace(/\d+(\.\d+)?/,
match => (parseFloat(match) * currencies[symbol]).toFixed(DECIMAL_DIGITS)
);
}
});
});
})();