分配泛型函数以在Typescript中进行委托 [英] Assigning generics function to delegate in Typescript

问题描述

我无法在Typescript（1.8）中编译此简单代码段

I can't get this simple code snippet to compile in Typescript (1.8)

function test<T>(a: string, input: T): T {
    return input
} 

const xyz: (a: string, b: number) => number = test<number>

我有一个接受委托的函数，但是将泛型函数转换为该委托格式需要我请执行以下额外步骤：

I have a function that takes a delegate, but converting the generics function into that delegate format requires me to perform this extra step:

const xyz: (a: string, b: number) => number = (a,b) => test<number>(a,b)

...这对我来说似乎并不理想。有什么想法为什么不起作用，或者是否还有其他语法可以实现同样的目的？

... which does not seem ideal to me. Any ideas why this does not work, or if there is another syntax to accomplish the same?

推荐答案

您不需要

const xyz: (a: string, b: number) => number = test;

（操场上的代码）

编译器会根据您为变量明确定义的类型将通用约束推断为数字。

另一种方法是：

The compiler infers the generic constraint to be number based on the type you explicitly defined for the variable.
Another way to do it is:

const xyz = test as (a: string, b: number) => number;

（操场上的代码）

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