[英]Typescript Generic Array of Interfaces
I have a problem with more advanced Generic types in TypeScript.我对 TypeScript 中更高级的泛型类型有疑问。
What I want to do is an array of data where the data
itself controlled by the type
like:我想要做的是一个数据数组,其中
data
本身由以下type
控制:
[
{
type: "T1",
content: number,
},
{
type: "T2",
values: {
id: number,
...
}
}
]
I kinda get stacked after describing the available types like:在描述了可用类型后,我有点堆积如山:
enum DataType {
T1 = "t1",
T2 = "t2"
}
So the result must look kinda like this, I guess:所以结果一定是这样的,我猜:
interface DataGeneric<T> {
[T extends DataType.T1]: { content: number },
[T extends DataType.T2]: { values: { id: number, ... } },
} ???
interface Data<T extends DataType = any(?)> extends DataGeneric<T>{
type: DataType,
// and all the other fields are generic from T = DataType
}
const someData: Data[] | undefined = fetchData();
// suggesting that the `type` of element[1] is "t2"
// and VSCode suggestions works correctly too,
// consider that there is an object-field `values` with `id` key
someData[1].values.id
Thanks in advance!提前致谢!
If you're checking an object's type
property against a string or numberliteral to discriminate what type of data the rest of the object is holding, then you probably want to use a discriminated union instead of generics.如果您要根据字符串或数字文字检查对象的
type
属性以区分 object 的 rest 所持有的数据类型,那么您可能想要使用可区分的联合而不是 Z56B97998B338B977DFF05A2888EEE。 That's basically a union type where the members of the union have a common discriminant key.这基本上是一种联合类型,其中联合的成员有一个共同的判别键。 In your case it could look like this:
在您的情况下,它可能如下所示:
enum DataType {
T1 = "t1",
T2 = "t2"
}
type Data =
{ type: DataType.T1, content: number } |
{ type: DataType.T2, values: { id: number } }
Then when you have a value data
of type Data
, you can check its type
property and the compiler knows that it should narrow data
to the right member of the union:然后,当您有一个
Data
类型的值data
时,您可以检查它的type
属性,编译器知道它应该将data
缩小到联合的正确成员:
declare const someData: Data[] | undefined;
if (someData) {
someData.forEach(data => {
if (data.type === DataType.T1) {
data.content.toFixed();
} else {
data.values.id.toFixed();
}
})
}
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