typescript 打字稿：在地图中使用数字作为键

Typescript : Using number as key in map

提问by Marty Pitt

This answersuggests it's valid to declare a map which enforces a numberas a key.

这个答案表明声明一个强制 anumber作为键的映射是有效的。

However, when I try the following in the playground, I get an error.

但是，当我在操场上尝试以下操作时，出现错误。

class Foo
{
    stringMap: { [s: string]: string; } = {};
    numberMap: { [s: number]: string; } = {};
}

numberMapgenerates the following compiler error:

numberMap生成以下编译器错误：

Cannot convert '{}'to '{ [s: number]: string; }': Index signatures of types '{}'and '{ [s: number]: string; }'are incompatible {}

无法转换'{}'为'{ [s: number]: string; }'：类型的索引签名'{}'并且'{ [s: number]: string; }'不兼容{}

What's the correct way to declare this?

声明这一点的正确方法是什么？

回答by Ryan Cavanaugh

I'm not 100% sure if this is a bug or not (I'd need to check the spec), but it's definitely OK to do this as a workaround:

我不是 100% 确定这是否是一个错误（我需要检查规范），但将其作为解决方法绝对可以：

class Foo
{
    stringMap: { [s: string]: string; } = {};
    numberMap: { [s: number]: string; } = <any>{};
}

If something's indexable by number you'd usually use []instead of {}, but that's obviously up to you.

如果某些内容可以按数字索引，您通常会使用[]代替{}，但这显然取决于您。