Typescript接口泛型:仅当T是联合类型'A | B‘时才允许泛型T

Question

export type Message = [
    {
        id: 'message',
        settings: ComponentSettings;
    }
];

type Industrial = [
    {
        id: 'title',
        settings: ComponentSettings;
    },
    {
        id: 'text',
        settings: ComponentSettings;
    }
];

我希望仅当T为'Message | Industrial‘时才允许T

export interface CardRef<T> {
    id: 'Industrial' | 'Message';
    childInstances?: T;
}

Answer 1

听起来您可能希望CardRef是一个联合类型，而不是一个带有泛型参数的类型：

export type CardRef =
    {
        id: 'Industrial';
        childInstances?: Industrial;
    }
    |
    {
        id: 'Message';
        childInstances?: Message;
    };

用法：

let x: CardRef = { id: 'Industrial' };
x.childInstances; // type is Industrial | undefined

let y: CardRef = { id: 'Message' };
y.childInstances; // type is Message | undefined

On the playground