为什么我在 TypeScript 中收到“类型‘字符串’不能用作索引类型”错误
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Why I'm getting "Type 'String' cannot be used as an index type" error in TypeScript
提问by JoelParke
I have a large amount of js code that uses a number of assoicative arrays that allow very fast access to objects. So I tried to port this code and failed. So clearly I don't understand TS well enough yet.
我有大量的 js 代码，它们使用了许多允许非常快速地访问对象的关联数组。所以我试图移植这个代码并失败了。很明显，我对 TS 的理解还不够好。
I have hunted for an the answer to this question and found suggestions to create an interface etc... but this seems a bit off the track.
我一直在寻找这个问题的答案，并找到了创建界面等的建议......但这似乎有点偏离轨道。
So tried the seeming obvious:
所以尝试了看似显而易见的：
class Foo {
allObjects: MyObject[];
constructor() {
this.allObjects = [];
}
}
where MyObject - simplified:
其中 MyObject - 简化：
class MyObject {
_id: String;
public getId(): String {
return this._id;
}
}
And I would believe that:
我会相信：
myObjectInstance: MyObject;
fooInstance.allObjects[myObjectInstance.getId()] = myObjectInstance;
would be fine... YET I see the lovely TS2342 error (An index expression argument must be of type 'string', 'number', or 'any') which makes no sense to me since getId() is a 'string'. It doesn't seem like this should be that hard. So your help would be greatly appreciated...
会很好......然而我看到了可爱的 TS2342 错误（索引表达式参数必须是“字符串”、“数字”或“任何”类型）这对我来说没有意义，因为 getId() 是一个“字符串” . 这似乎不应该那么难。所以你的帮助将不胜感激......
回答by Paarth
Use lowercase stringfor the type of MyObject._id
使用小写string的类型MyObject._id
