# function type expression

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{% tab title="📗 參考" %}
* 📘 [Function Type Expression](https://www.typescriptlang.org/docs/handbook/2/functions.html#function-type-expressions)
{% endtab %}

{% tab title="Second Tab" %}

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```typescript
//                  ╭ ⭐️ func type expr ╮
type GreetFunction = (a: string) => void ;

function greeter(fn: GreetFunction) {
  // ...
}
```
