Router condition run

I have api I want to run this api with different conditions it is like
this is my config

	config := api.Config{
		Version:          VERSION,
		Host:             Setting.Host,
        Key:              Setting.Key,
		Https:            Setting.Https,
		Enable:           Setting.Enable,
	}

if in config yaml Enable is true I want to run the router with extra value

	if config.Enable {
		test_f := func() (func(), error) {
			return df, nil
		}
		router := api.MakeRouter(&config, test_f)
	}

when enable is false

    else {
        router := api.MakeRouter(&config, nil)

    }

but my problem is that I have another condition. in here I get an error which is undefined: router

	if config.Https {
		go router.RunTLS(config.Host, config.Key)
	} else {
		go router.Run(config.Host)
	}
```
how can I solve this

</details>


# 答案1
**得分**: 1

你正在在一个代码块内定义变量`router`，这意味着它的作用域仅限于该代码块内部，在该代码块外部是不存在的。你需要在代码块外部定义它，并在内部进行赋值：

```go
var router api.WhateverTypeRouterIs
if config.Enable {
    test_f := func() (func(), error) {
        return df, nil
    }
    router = api.MakeRouter(&config, test_f)
} else {
    router = api.MakeRouter(&config, nil)
}
```

或者，另一种方法是，由于只有一个值不同，在`if`代码块中处理该值，并在外部创建路由器：

```go
var test_f func() (func(), error)
if config.Enable {
    test_f = func() (func(), error) {
        return df, nil
    }
}
router := api.MakeRouter(&config, test_f)
```

一般来说，我更倾向于使用后一种方法，因为它更清晰明了，但如果在两种情况下有更多的变化，那么第一种方法可能更合适。

标识符的作用域在规范中有详细说明：https://go.dev/ref/spec#Declarations_and_scope

<details>
<summary>英文:</summary>

You&#39;re defining the variable `router` inside a block, which means it is scoped to that block; it doesn&#39;t exist outside that block. You need to define it outside the block, and assign to it inside:


    var router api.WhateverTypeRouterIs
    if config.Enable {
        test_f := func() (func(), error) {
            return df, nil
        }
        router = api.MakeRouter(&amp;config, test_f)
    } else {
        router = api.MakeRouter(&amp;config, nil)
    }

Or, alternatively, since only one value is different, deal with that value only in the `if` block, and create the router outside:

    var test_f func() (func(), error)
    if config.Enable {
        test_f = func() (func(), error) {
            return df, nil
        }
    }
    router := api.MakeRouter(&amp;config, test_f)

The latter would be my preference in general because it&#39;s more clear what&#39;s happening, but if more things are likely to change between the two cases, that might be an argument for the first approach.

Identifier scope is detailed in the spec: https://go.dev/ref/spec#Declarations_and_scope

</details>