Switch Case 语句中的重复常量声明错误 [英] Error Duplicate Const Declaration in Switch Case Statement

问题描述

我有以下代码，但收到错误重复声明 query_url".

I have the following code and I get the error 'Duplicate Declaration query_url'.

  switch(condition) {
    case 'complex':
      const query_url = `something`;
      break;
    default:
      const query_url = `something`;
      break;
  }

我知道 query_url 被声明了两次，这是不对的.但我不知道如何解决这个问题.有人可以帮助了解使这项工作的正确方法是什么吗?

I understand that query_url is getting declared twice which isn't right. But i don't know how to resolve this. Can someone please help on what should be the correct way to make this work?

推荐答案

如果您需要在每种情况下重新声明相同的变量，请参阅 @Bergi 的回答如下

如果 query_url 可以根据 switch 分支有多个值，显然你需要一个变量(用 var 或 let 声明).

if query_url can have multiple values depending on the switch branch obviously you need a variable ( declare either with var or let ).

const 设置一次并保持这种状态.

const is set once and stays that way.

使用 let 的示例

let query_url = '';
switch(condition) {
  case 'complex':
    query_url = `something`;
    break;
  default:
    query_url = `something`;
    break;
}

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