number-currency-formatting.js

// https://blog.tompawlak.org/number-currency-formatting-javascript  

function formatNumber (num) {
    return num.toString().replace(/(\d)(?=(\d{3})+(?!\d))/g, "$1,")
}

console.info(formatNumber(2665));      // 2,665
console.info(formatNumber(102665));    // 102,665
console.info(formatNumber(111102665)); // 111,102,665


// Currency Formatting

function currencyFormat (num) {
    return "$" + num.toFixed(2).replace(/(\d)(?=(\d{3})+(?!\d))/g, "$1,")
}

console.info(currencyFormat(2665));   // $2,665.00
console.info(currencyFormat(102665)); // $102,665.00

// ------------

function currencyFormatDE (num) {
    return num
       .toFixed(2) // always two decimal digits
       .replace(".", ",") // replace decimal point character with ,
       .replace(/(\d)(?=(\d{3})+(?!\d))/g, "$1.") + " €" // use . as a separator
}

console.info(currencyFormatDE(1234567.89)); // output 1.234.567,89 €


// -----------
var currency = "R$ 1.100,77";
var currency = currency.replace(".", "").replace(",", ".")currency.replace("R$ ", "");
var currency = parseFloat(currency)

Muito bom!