我应该在 ReactJS 中使用 for 循环吗？ 当输入更改时，还有其他方法可以同时更改多个元素吗？

Question

I'm creating a POS system with ReactJS. Should I use a for loop to calculate the total amount? Is there any other way to do this?

let product = testProducts;
let subtotalEl = document.getElementsByClassName("Subtotal");
let quantity = document.getElementsByClassName("Quantity");
for (var i = 0; i < product.length; i++) {
  subtotalEl[i].innerHTML = product[i].UnitPrice * quantity[i].value;
}

Answer 1

1. You are not using react js, your code looks like JavaScript.
2. Yes, you can use a loop to add, but in React it is recommended to use map for iterations.

For example:

const sum = array_object
  .map((item) => item.quantity)
  .reduce((prev, curr) => prev + curr, 1);

As you can see, map was used to go through the array, and reduce to add the values.