英文:
Require exactly two of three properties with TypeScript
问题
我有一些React组件，需要精确地有三个属性中的两个来表示时间范围：from、to或duration。任何两个属性的组合都足以正确推导出第三个属性。因此，我希望TypeScript强制要求确切需要两个这些属性。
我尝试定义props如下：
type RangeProps =
| {
from: Date
to: Date
}
| {
from: Date
duration: number
}
| {
duration: number
to: Date
}
但是当我提供了这三个属性 (<Range from={startDate} duration={duration} to={endDate} />)，TypeScript没有抱怨。如何让它抱怨呢？
英文:
I have a few React components that need exactly two of three props to represent a time range: from, to, or duration. Any combination of two is enough to derive the third one correctly. So I want TypeScript to enforce that exactly two of these props is required.
I tried defining props like this:
type RangeProps =
| {
from: Date
to: Date
}
| {
from: Date
duration: number
}
| {
duration: number
to: Date
}
But when I supply all three props (<Range from={startDate} duration={duration} to={endDate} />, TypeScript doesn't complain. How can I get it to complain?
答案1
得分: 2
You can use the type never, this type means that the property cannot be passed:
type RangeProps =
| {
from: Date;
to: Date;
duration?: never;
}
| {
from: Date;
duration: number;
to?: never;
}
| {
duration: number;
to: Date;
from?: never;
};
英文:
You can use the type never, this type means that the property cannot be passed:
type RangeProps =
| {
from: Date;
to: Date;
duration?: never;
}
| {
from: Date;
duration: number;
to?: never;
}
| {
duration: number;
to: Date;
from?: never;
};
答案2
得分: 1
以下是您要翻译的内容：
playground
use this generic trick T extends never? T : some type check logic
T extends any? some type check logic : never also work
英文:
use this generic trick T extends never? T : some type check logic
T extends any? some type check logic : never also work
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