Typescript 枚举、接口和映射
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Typescript enum, interface and mapping
提问by Ben
In TypeScript, in an array or similar data structure, how can I map a string to an id, while ensuring that only a certain range of ids is allowed?
在 TypeScript 中，在数组或类似数据结构中，如何将字符串映射到 id，同时确保仅允许特定范围的 id？
Here is what I want to do. This works fine. However, I am wondering if there is a more concise way of achieving this?
这是我想要做的。这工作正常。但是，我想知道是否有更简洁的方法来实现这一目标？
enum ETypeId {
alpha = "a",
beta = "b",
gamma = "g"
}
interface IType {
id: ETypeId,
title: string,
}
myTypes: IType[] = [
{ id: ETypeId.alpha, title: "Alpha" },
{ id: ETypeId.beta, title: "Beta" },
{ id: ETypeId.gamma, title: "Gamma" }
];
As is, I have to do the following to get from the idto the title:
按原样，我必须执行以下操作才能从id到title：
function getTypeForTypeId( typeId: ETypeId ): IType {
return myTypes.find( type => type.id == typeId );
}
Can I use a different data structure that makes some of the above code more concise, or is this already as good as it gets?
我可以使用不同的数据结构来使上面的一些代码更简洁，还是已经达到了它的目的？
Explanation:
解释：
"a"is what gets stored in my databaseETypeId.alphais how I access it in my code"Alpha"is what gets displayed to the user.
"a"是存储在我的数据库中的内容ETypeId.alpha是我在代码中访问它的方式"Alpha"是显示给用户的。
回答by mykhailo.romaniuk
Agree with Sergi Dote Teixidor'sanswer that Mapis the best option for such problem. However, based on the described problem, I think that it could be simplified to Map<ETypeId, string>:
同意Sergi Dote Teixidor 的回答，即Map是解决此类问题的最佳选择。但是，基于所描述的问题，我认为它可以简化为Map<ETypeId, string>：
enum ETypeId {
alpha = "a",
beta = "b"
}
const types: Map<ETypeId, string> = new Map( [
[ ETypeId.alpha, "Alpha" ],
[ ETypeId.beta, "Beta" ],
]);
Just in case you want to initialize your structure once and make TypeScript protect you from changing values inside your map:
以防万一您想初始化一次结构并使 TypeScript 保护您免受更改地图中的值的影响：
enum ETypeId {
alpha = "a",
beta = "b"
}
interface ReadonlyMap<TKey, TValue> {
get(key: TKey):TValue;
}
const types: ReadonlyMap<ETypeId, string> = new Map( [
[ ETypeId.alpha, "Alpha" ],
[ ETypeId.beta, "Beta" ],
]);
// Static analyzer error if you try to change the value:
types.set(ETypeId.alpha, "NewValue");
回答by Sergi Dote Teixidor
you can use a map:
你可以使用地图：
- you can retrieve directly any element
- you can loop all elements if you want
- 您可以直接检索任何元素
- 如果需要，您可以循环所有元素
example:
例子：
enum ETypeId {
alpha = "a",
beta = "b",
gamma = "g"
}
interface IType {
id: ETypeId,
title: string,
}
const myMap: Map<string, IType> = new Map( [
[ ETypeId.alpha, { id: ETypeId.alpha, title: "Alpha" } ],
[ ETypeId.beta, { id: ETypeId.beta, title: "Beta" } ],
[ ETypeId.gamma, { id: ETypeId.gamma, title: "Gamma" } ]
]);
console.log(myMap.get(ETypeId.alpha)) // -> {id: "a", title: "Alpha"}
