javascript nodejs舍入错误

Question

我希望每件事都准确、精确地加起来，我不能让总数少一分钱。

var buy_amount = 132.32000000;                      //amount in bitcoin
var buy_amount_satoshi = buy_amount*100000000;      //amount in satoshi
var sell_rate = 10.00000000;                        //USD rate
var spend_usd = buy_amount_satoshi*sell_rate;   //total USD
var spend_display = spend_usd/100000000;        //total USD user display

console.log(spend_usd.toFixed(8));              //132320000000.00000000
console.log(spend_display.toFixed(8));              //1323.20000000

jsfiddle.net/XjLLS/

1. 用100000000乘以这个数字就可以得到no。萨托西斯- 正确的货币处理
2. 将金额乘以比率。
3. 将8位小数添加到结果中

我做得对吗？我很感激你的帮助！

更新：--我现在正在使用bigdecimal.js库，并编写了以下代码片段：

var bigdecimal = require("bigdecimal");

var mode = bigdecimal.RoundingMode.HALF_EVEN(); //default: DOWN
var satoshi = new bigdecimal.BigDecimal("100000000");

var buy_amount = new bigdecimal.BigDecimal("132.32000000"); //amount in bicoin
var amount_minor = buy_amount.multiply(satoshi); //amount in satoshi
var sell_rate = new bigdecimal.BigDecimal("10.00000000"); //sell rate usd
var spend_minor = amount_minor.multiply(sell_rate);
var user_spend = spend_minor.divide(satoshi, 8, mode); //total usd user must spend
var user_display = user_spend.toString();
console.log(user_display);

jsfiddle.net/wwpWA/

默认的舍入模式是向下的，但我将其设置为HALF_EVEN，也就是银行家的四舍五入(银行家的四舍五入在使用货币时很常见)

我希望所有四舍五入的错误现在都消失了！如果我错了，请纠正我！

Answer 1

尝尝这个

var buy_amount = 132.32000000;                     
var buy_amount_satoshi = (parseFloat(buy_amount)*100000000).toFixed(8);     
var sell_rate = 10.00000000;                        
var spend_satoshi = (parseFloat(buy_amount_satoshi)*parseFloat(sell_rate)).toFixed(8);   
var spend_display = (parseFloat(spend_satoshi)/100000000).toFixed(8);