在Prom中使用Promise作为返回类型 [英] Using Promise as return type in Flow

问题描述

我正在使用Flow 0.30.0。我有一个函数返回一个promise：

I'm using Flow 0.30.0. I have a function that returns a promise:

function process(callback:Function):Promise {
  return new Promise((r,re) => callback)
}

Flow引发错误，抱怨：

Flow raises an error, complaining:

function process(callback:Function):Promise {
                                    ^^^^^^^ Promise. Application of polymorphic type needs <list of 1 argument>. (Can use `*` for inferrable ones)

这适用于尝试流程，但不在本地。问题的任何想法？

This works in Try Flow, but not locally. Any ideas of the issue?

推荐答案

根据流程更改日志，v0.28.0中引入了一个更改，它使类型参数显式化。明确将返回类型设置为 Promise< any> 应该可以解决您的问题。

According to the flow changelog there was a change introduced in v0.28.0 which made type arguments explicit. Explicitly setting the return type to Promise<any> should fix your issue.

或者您可以将以下标志设置为false，尽管这是一个临时标志，将来会被删除

Alternatively you can set the following flag to false, although this is a temporary flag which will be removed in the future

experimental.strict_type_args = false

https://github.com/facebook/flow/blob/master/Changelog.md#v0280

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