typescript - 将数组定义为具有强制值，以及可选的其他值

Question

我正在尝试做这样的事情：

我有Student类型和Teacher类型，它们是相似的，除了所有的老师总是有"staffroom_access"特权。学生可以选择拥有此特权。

我试图用这条线来做这件事：

privileges: Role[] extends ["staffroom_access"]

但这给了我：

Property 'privileges' of exported interface has or is using private name ''.(4033)

完整代码：

type Role = "staffroom_access" | "sportsroom_access"; 

type Teacher = {
    name: string; 
    privileges: Role[] extends ["staffroom_access"]; //Property 'privileges' of exported interface has or is using private name ''.(4033)
}

type Student = {
    name: string; 
    privileges: Role[]; 
}

const mrJones: Teacher = {
    name: "Mr Jones",
    privileges: [] //Should error
}; 

const mrSmith: Teacher = {
    name: "Mr Smith",
    privileges: ["staffroom_access"] //Should be Ok 
}; 

我将如何实现我想要的功能？

标签： typescript

Answer 1

您可以在元组类型中使用其余元素，如下所示：

type Teacher = {
    name: string; 
    privileges: ["staffroom_access", ...Role[]];
}

这将为您提供所需的确切行为。