有3個值，
previousBalanceTotal= 這是銀行賬戶的總余額previousWithdrawTotal= 我以前提取過這么多總價值newWithdrawAmount= 我現在要提取的金額，
我現在需要設定newWithdrawTotal。
我想做的是，如果我newWithdrawAmount的比我的大previousBalanceTotal，我想顯示一個警報，并保持newWithdrawTotal之前的WithdrawTotal，否則添加 newWithdrawAmount到previousWithdrawTotal并保留它newWithdrawTotal。
newWithdrawAmount我嘗試了以下代碼，但它在大于時不起作用previousBalanceTotal。它回傳一個函式并且不顯示警報。你能幫我解決這個問題嗎？
const newWithdrawTotal = (newWithdrawAmount < previousBalanceTotal) ? (newWithdrawAmount previousWithdrawTotal) : function () {
console.log(previousWithdrawTotal);
alert('you can not withdraw more than your balance');
return previousWithdrawTotal;
};
console.log(newWithdrawTotal);
uj5u.com熱心網友回復：
你沒有呼叫函式，你只是回傳它。使用 IIFE 立即呼叫匿名函式。
const newWithdrawTotal = (newWithdrawAmount < previousBalanceTotal) ?
(newWithdrawAmount previousWithdrawTotal) : (function() {
console.log(previousWithdrawTotal);
alert('you can not withdraw more than your balance');
return previousWithdrawTotal;
})();
console.log(newWithdrawTotal);您實際上并不需要該功能，您可以改用逗號運算子。
const newWithdrawTotal = (newWithdrawAmount < previousBalanceTotal) ? (newWithdrawAmount previousWithdrawTotal) : (
console.log(previousWithdrawTotal),
alert('you can not withdraw more than your balance'),
previousWithdrawTotal
);
console.log(newWithdrawTotal);uj5u.com熱心網友回復：
試試這個代碼塊
const newWithdrawAmount = 13000;
const previousBalanceTotal = 12000;
const previousWithdrawTotal = 300;
var newWithdrawTotal;
function calc() {
if(newWithdrawAmount < previousBalanceTotal) {
return newWithdrawTotal = newWithdrawAmount previousWithdrawTotal
} else {
console.log(previousWithdrawTotal);
alert('you can not withdraw more than your balance');
return newWithdrawTotal = previousWithdrawTotal;
}
}
calc()
console.log(newWithdrawTotal);
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標籤：javascript 功能 返回 条件运算符
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