JavaScript nodejs舍入錯誤

Question

我希望一切都準確，加起來，我不能讓總數成爲一分錢。

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. 乘以量與億拿到沒有。 satoshis的 - Proper Money Handling
2. 乘以量與速度
3. 加入8位小數的結果

我是這樣做的權利？我感謝您的幫助！

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UPDATE： 我現在使用bigdecimal.js庫，並提出以下片段：

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/

默認舍入模式但我把它設置爲HALF_EVEN aka銀行家的四捨五入（銀行家的四捨五入是常見的工作時用錢）

我希望所有的舍入錯誤現在都消失了！如果我錯了，請糾正我！

Answer 1

試試這個

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);