当某个条件变为 True 时，有没有办法重新定义 "let" 值？

Question

温柔点:

我是 Javascript 的新手，很好奇我将如何处理运行重新定义“let”值的 for 循环 [或建议更合适的不同循环]在循环中的条件变为 True 之后。当最后一个“else if”条件变为 True 时，它会通过向其添加 const add_to 来重新定义 Value1 值，然后再次开始前两个条件检查。无限循环？

我在下面提供了我当前代码的示例：

const fetch = require('node-fetch');
const api_url = 'https://an-api-i-am-using-that-returns-Value1.com'
let Value1 = 100;
const add_to = 10;

async function getTotal() {

    const response = await fetch(api_url);

    Number_Returned = await response.json();
    Number_Left = Value1 - Number_Returned
    Time_Left = Number_Left * 60;

    if (Number_Left > 0){
        console.log(Number_Left)

        var d = parseInt(Time_Left / (3600 * 24));
        console.log(d)

        nd = Time_Left % (24 * 3600);
        var h = parseInt(nd/3600);
        console.log(h)

        Time_Left %= 3600;
        var m = parseInt((Time_Left/60));
        console.log(m)

        const longEnUSFormatter = new Intl.DateTimeFormat('en-US', { dateStyle: 'full', timeStyle: 'long' });

        var date = new Date();
        date.setMinutes(date.getMinutes() + (d * 24 * 60) + (h * 60) + m);
        console.log(longEnUSFormatter.format(date))
    }
    else if (Number_Left == 0 && Value1 == Number_Returned) {
        console.log(Number_Left)

        d = "no";
        console.log(d)
        h = "no";
        console.log(h)
        m = "no";
        console.log(m)
        date = "Today";
        console.log(date)
    }
    else if (Number_Left < 0) {
        console.log(Number_Left)

        d = "didn't work";
        console.log(d)
        h = "didn't work";
        console.log(h)
        m = "didn't work";
        console.log(m)
        date = "didn't work";
        console.log(date)
        Value1 =+ add_to;
    }
}

async function begin(){
    console.log('calling');
    const result = await getTotal();
    console.log(Value1);
}

begin();

目前，脚本 returns 在运行之后产生以下结果（示例结果）：

当 (Number_Left > 0) 为真时：

calling
3
0
0
3
Tuesday, April 27, 2021 at 7:55:59 PM GMT+1

当 (Number_Left == 0 && Value1 == Number_Returned) 为真时：

calling
0
no
no
no
Today
98273492

当 (Number_Left < 0) 为真时：

calling
-7
didn't work
didn't work
didn't work
didn't work
10

重申一下，一旦最后一个条件变为真，我想将 const add_to 添加到 let 值 Value1，开始 (Number_Left > 0) 和 (Number_Left == 0 && Value1 == Number_Returned)再次检查条件。

让我知道是否可以更具体地说明我要完成的任务。提前致谢。

Answer 1

语法是 += 而不是 =+ 当你想添加值并设置它时

Answer 2

如果您更改：

，您似乎会得到想要的结果

Value1 =+ add_to;

至（注意 addition assignment operator）：

Value1 += add_to;

Answer 3

为了执行我需要此代码执行的操作，我不得不重写它。它可能不是最好的编码，但它适用于我想要完成的事情：

const api_url = 'https://an-api-i-am-using-that-returns-Value1.com';

    async function getTotal(){
        resp = await fetch(api_url);
        Number_Returned = await resp.text();
        return Number_Returned
    }

    async function checkValue1(){
        Value1 = 100;
        const add_to = 10;
        cur = await getTotal();

        if (Value1>=cur){
            return cur
        }
        else if (Value1<cur){
            Value1 = Value1 + add_to
            return cur
        }
    }

    async function calculateTotal(){
        const theValue1 = await checkValue1();
        const numDifference = 2880;
        let numLeft = (Value1 - numDifference) - theValue1;
        let timeDelta = numLeft * 60.097;
        return timeDelta
    }

    async function calcDate(){
        let timeLeft = await calculateTotal();
        let d = parseInt(timeLeft / (3600 * 24));
        document.getElementById('days').innerHTML = d;
        nd = timeLeft % (24 * 3600);
        let h = parseInt(nd/3600);
        document.getElementById('hours').innerHTML = h;
        timeLeft %= 3600;
        let m = parseInt((timeLeft/60));
        document.getElementById('mins').innerHTML = m;
        const longEnUSFormatter = new Intl.DateTimeFormat('en-US', { dateStyle: 'full', timeStyle: 'long' });
        let date = new Date();
        date.setMinutes(date.getMinutes() + (d * 24 * 60) + (h * 60) + m);
        document.getElementById('date').innerHTML = longEnUSFormatter.format(date);
}

calcDate();

当某个条件变为 True 时，有没有办法重新定义 "let" 值？

Is there a way to redefine a "let" value when a certain condition becomes True?

javascript

loops

for-loop

timedelta

conditional-statements