avoid rounding errors in javascript with bigdecimal? a user submits a buy request: 0.0104 BTC at a rate of 345.92 EUR

config:

var mode = RoundingMode.HALF_EVEN();
var satoshi = new BigDecimal("100000000");


user input:

var btc_b = new BigDecimal("0.0104");
var rate_b = new BigDecimal("345.92");


convert amount to smallest unit:

var btc_s = btc_b.multiply(satoshi);


btc * rate = spend:

var eur_s = btc_s.multiply(rate_b).setScale(0,mode);
console.log(eur_s.longValue());

output: 359756800


eur / smallest unit:

var eur_b = eur_s.divide(satoshi, 8, mode);
console.log(eur_b.longValue());

output: 3.597568


but since eur has only 2 decimals:

console.log(eur_b.setScale(2,mode).longValue());

output: 3.6


i assume the user must spend 3.6 EUR for 0.0104 BTC at a rate of 345.92 EUR

here's a fiddle: jsfiddle.net/nvkja98c/

please correct me if i'm wrong!
This is not a rounding problem.  The 3.6 EUR is correctly rounded to two decimals from 3.597568 EUR.  

Computers don't know when we want to see trailing zeros.  The problem is formatting:

console.log(eur_b.setScale(2,mode).longValue().toFixed(2));

output: 3.60


(fiddle)