Javascript 什么是 Typescript 中的“导出类型”？
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What is `export type` in Typescript?
提问by hackjutsu
I notice the following syntax in Typescript.
我注意到 Typescript 中的以下语法。
export type feline = typeof cat;
As far as I know, typeis not a built-in basic type, nor it is an interface or class. Actually it looks more like a syntax for aliasing, which however I can't find reference to verify my guess.
据我所知，type不是内置的基本类型，也不是接口或类。实际上它看起来更像是别名的语法，但是我找不到参考来验证我的猜测。
So what does the above statement mean?
那么上面的说法是什么意思呢？
回答by James Monger
This is a type alias- it's used to give another name to a type.
这是一个类型别名- 它用于为类型提供另一个名称。
In your example, felinewill be the type of whatever catis.
在您的示例中，feline将是任何类型cat。
Here's a more full fledged example:
这是一个更完整的示例：
interface Animal {
legs: number;
}
const cat: Animal = { legs: 4 };
export type feline = typeof cat;
felinewill be the type Animal, and you can use it as a type wherever you like.
feline将是 type Animal，您可以将其用作任何您喜欢的类型。
const someFunc = (cat: feline) => {
doSomething();
};
exportsimply exports it from the file. It's the same as doing this:
export只需从文件中导出它。这与执行此操作相同：
type feline = typeof cat;
export {
feline
};
