如何使用泛型类型为箭头函数编写流类型

Question

如何为以下代码编写flowtype？

function参数是泛型类型的数组.

const fn = (array) => Promise.resolve(array[0]);

Answer 1

const fn = <T>(array: Array<T>): Promise<T> => Promise.resolve(array[0]);

相关文档:https://flow.org/en/docs/types/generics/