Format number to always show 2 decimal places

Question

I would like to format my numbers to always display 2 decimal places, rounding where applicable.

Examples:

number     display
------     -------
1            


        

Answer 1

function number_format(string,decimals=2,decimal=',',thousands='.',pre='R$ ',pos=' Reais'){
  var numbers = string.toString().match(/\d+/g).join([]);
  numbers = numbers.padStart(decimals+1, "0");
  var splitNumbers = numbers.split("").reverse();
  var mask = '';
  splitNumbers.forEach(function(d,i){
    if (i == decimals) { mask = decimal + mask; }
    if (i>(decimals+1) && ((i-2)%(decimals+1))==0) { mask = thousands + mask; }
    mask = d + mask;
  });
  return pre + mask + pos;
}
var element = document.getElementById("format");
var money= number_format("10987654321",2,',','.');
element.innerHTML = money;

#format{
display:inline-block;
padding:10px;
border:1px solid #ffffd;
background:#f5f5f5;
}

Test 123456789