typescript - 如何在 TypeScript 的通用类型参数中使用联合类型作为约束

Question

似乎不可能有一个受联合类型约束的泛型类。基本上是这样的：

class Shoe {
    constructor(public size: number){}
}

class Dress {
    constructor(public style: string){}
}

class Box <T extends Shoe | Dress > {
}

然后这个：

// because move can move multiple boxes of Box of shoes or Box of dress
class Move<B extends Box<Shoe>[] | Box<Dress>[]> {
    private stuff: B;
    constructor(public toMove: Box<Shoe>[] | Box<Dress>[]) {
        this.stuff = toMove // this does not compile
    }

}

或者如何实现？我有一个Playground 链接来展示这种情况

标签： typescriptgenericstypes

Answer 1

我想，这又是对你真实意图的猜测，这应该足够了：

class Shoe {
    constructor(public size: number){}
}

class Dress {
    constructor(public style: string){}
}

class Box <T extends Shoe | Dress > {
}


// because move can move multiple boxes of Box of shoes or Box of dress
class Move<B extends Box<Shoe>[] | Box<Dress>[]> {
    private stuff: B;
    constructor(public toMove: B) {
        this.stuff = toMove;
    }

}