An example of functional programing using a higher order function

myHigherOderFunction.js

let formatCurrency = function( currencySymbol, decimalSeparator ) {
  return function( value ) {
    let wholePart = Math.trunc(value / 100);
    let fractionalPart = value % 100;
    if ( fractionalPart < 10 ) fractionalPart = '0' + fractionalPart;
    return `${currencySymbol}${wholePart}${decimalSeparator}${fractionalPart}`;
  }
}

let formatter = formatCurrency( '$', '.' );

console.log(formatter(0));
console.log(formatter(1209));