条件在打字稿中重叠

发布于 2025-02-01 22:35:29 字数 505 浏览 3 评论 0 原文

假设我有一些这样的简单逻辑：

let bool = false

const seven = 7
const arr = [1,2,3,4,5,6,7]
    
arr.forEach(element => {
    if (element === seven) {
        bool = true
    }
});

如果“ bool”设置为true，现在我不打算呼叫函数：

if (bool === true){
    doSomething()
}

在这种情况下，Typescript给出了错误：

This condition will always return 'false' since the types 'false' and 'true' have no overlap.

Typescript抱怨即使从逻辑上讲，我知道Bool将由触发条件块的时间。我该如何解决？

原文

Lets say I have some simple logic like this:

let bool = false

const seven = 7
const arr = [1,2,3,4,5,6,7]
    
arr.forEach(element => {
    if (element === seven) {
        bool = true
    }
});

Now I wan't to call a function if "bool" has been set to true:

if (bool === true){
    doSomething()
}

Typescript gives an error in this case:

This condition will always return 'false' since the types 'false' and 'true' have no overlap.

Typescript complains even though logically I know that bool will be true by the time the condition block is triggered. How do I resolve this?

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俯瞰星空 2025-02-08 22:35:29

我不知道Typescript编译器会在这样的事情上抱怨，但是这再次是具有这样一种条件语句的一种奇怪的方式，因为：

if (bool === true)

但是

if (bool)

，您可以：

以正常方式写条件：<代码： if（bool）{...} （强烈推荐）
迫使要为布尔值的类型： if（（（bool as as boolean）==== true）{...} （它有效，但请不要这样）

I did not know that the Typescript compiler would complain on something like this, but again it's a strange way to have such a condition statement since:

if (bool === true)

is the same as:

if (bool)

But yeah you can either:

Write the condition in a normal way: if (bool) { ... } (highly recommended)
Force the type to be boolean: if((bool as boolean) === true ) { ... } (it works but please don't do this)