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javascript - Print value in more than one const statement

问题描述

Related script:

window.onload = function calcPreco() {
for(const cloud of Array.from(document.getElementsByName("cloud"))) {
    fetch("_config/buscar_valor.php?id="+cloud.getAttribute("cloudid")+"&periodicidade=monthly")
     .then(res => res.text())
     .then(preco => {
        preco -= cloud.getAttribute("desconto");
        const valor = cloud.querySelector(".mostrar_valor").innerText = preco.toFixed(2).replace('.', ',');
     })
    }
}

I need it to print to another <span> with another class, but before doing the subtraction.

I tried something like that, but it did not work:

.then(preco => {
        const valor = cloud.querySelector(".NEW_CLASS").innerText = preco.toFixed(2).replace('.', ',');
        preco -= cloud.getAttribute("desconto");
        const valor = cloud.querySelector(".mostrar_valor").innerText = preco.toFixed(2).replace('.', ',');
     })

That is, it must first print the original value, and then the value with the subtraction done.

How to use two const statements in this case?

标签： javascriptjqueryajax

解决方案

使用 var 或 const 时，将其视为分配内存位置。当您在同一范围内分配 2 个内存位置时，它不知道该怎么做。因此，请使用不同的名称或从变量声明中删除 var/const。一个好的做法是定义然后使用：

var someVariable;
if(condition){
   someVariable = 'some answer';
}
else
{
   someVariable = "some other answer';
}

或连接：

var someVariable;
someVariable = "some"; // mostly this and the line above will be one line.
someVariable += " answer";

另外，如果您这样做：

valor = "some html";
valor = "some other html"; // This will overwrite the first answer.

也很好读：

https://airbrake.io/blog/javascript-error-handling/redeclaration-formal-parameter-x

可能您正在寻找的内容：

var valor = cloud.querySelector(".NEW_CLASS").innerText = preco.toFixed(2).replace('.', ',');
preco -= cloud.getAttribute("desconto");
valor += cloud.querySelector(".mostrar_valor").innerText = preco.toFixed(2).replace('.', ',');

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