Question

我不知道如何用打字稿定义班级集合的类型：

当我编译以下代码时，我遇到了错误：

    class Wall{
        brick: string;

        constructor(){
            this.brick = "jolies briques oranges";
        }

        // Wall methods ...
    }

class Critter {
    CritterProperty1: string[];
    CritterProperty2: string;

    constructor() {
        this.CritterProperty1 = "n ne e se s so o no".split(" ");        
    }

    // Critter methods ...
}

type legendObjectType = Critter | Wall;

interface Ilegend {
    [k: string]: legendObjectType; 
}

// i've got an issue to define the type of 'theLegend' Object
let theLegend: Ilegend = {
    "X": Wall,
    "o": Critter
}

错误TS2322：键入＆＃39; {＆＃34; X＆＃34;：typeof Wall; ＆＃34; o＆＃34;：typeof Critter; }＆＃39;不是可归类为＆＃39; Ilegend＆＃39;。

虽然我可以编译它，如果＆＃34;类墙＆＃34;是空的。

有谁知道如何定义这类课程的类型？

让theLegend = { ＆＃34; X＆＃34;：墙，＆＃34; o＆＃34;：小动物}

（这是eloquent javascript第7章的例子，而不是我试图在打字稿中转录）

修改

我完成了Rico Kahler的答案，使用抽象类来避免使用联合类型

abstract class MapItem {
    originChar: string;

    constructor(){}
}

class Wall extends MapItem {
    brick: string;

    constructor(){
        super();
        this.brick = "jolies briques oranges";
    }

    // Wall methods ...
}

class Critter extends MapItem {
    CritterProperty1: string[];
    CritterProperty2: string;

    constructor() {
        super();
        this.CritterProperty1 = "n ne e se s so o no".split(" ");        
    }

    // Critter methods ...
}

interface Ilegend {
    [k: string]: new () => MapItem; 
}

let theLegend: Ilegend = {
    "X": Wall,
    "o": Critter
}

感谢＆＃39; S

Answer 1

您的问题在于您的对象theLegend。

Typescript需要一个Wall或Critter的实例，而是你为它提供一个类型。

let theLegend: Ilegend = {
    "X": Wall, // `Wall` is a type not an instance, it is `typeof Wall` or the Wall type
    "o": Critter // `Criter` is a type not an instance
}

以下内容将起作用：

let theLegend: Ilegend = {
    X: new Wall(), // now it's an instance!
    o: new Critter()
}

修改

现在阅读你链接的javascript页面，似乎我错过了你的意图。如果你想创建一个接受构造函数的接口，那么我将按如下方式键入Ilegend：

interface Legend { [k: string]: new () => (Critter | Wall) } // now you can define an object with this type let legend: Legend = { // here `Critter` actually refers to the class constructor // that conforms to the type `new () => (Critter | Wall)` instead of just a type something: Critter, somethingElse: Wall } const critter = new legend.something() // creates a `Critter` const wall = new legend.somethingElse() // creates a `Wall` // however, the type of `critter` and `wall` are both `Critter | Wall`. You'd have to use type assertion (i.e. casting) because typescript can't tell if its either a Critter or a Wall

现在接口允许任何字符串成为键，并且它希望每个值都是一个函数，您可以调用new来获取Critter或Wall

typescript：定义类集合的类型

1 个答案: