javascript - set 不是函数 Typescript

Question

我想在 typescript Map 中添加对象，但遇到问题:

TypeError: this.things.set is not a function.

我的代码如下所示:

Thing.ts:

export class Thing {
    id: string;
    title: string;

    constructor(id, title) {
        this.title = title;
        this.id = id;
    }
    getID(){
        return this.id;
    }
}

机器人.ts

export class Robot {
    things = new Map<string, Thing>();       

    constructor() {
        this.things = {};
    }
    public addThing(t: Thing) {
        this.things.set(t.id, t);
    }
    public showThings(){
        return this.things;
    }
}

还有一个简单的 Web 界面来获取用户的输入(标题和 ID)并将其添加到 map 中。它看起来像这样:

索引.ts

let r: Robot = new Robot(); 
//...
app.get("/api/newThing", (req, res) => {
    if (req.query.id === undefined | req.query.title === undefined) {
        res.status(400);
        res.setHeader("Content-Type", "text/html; charset=utf-8");
        res.end("error here");
    } else {
        console.log(req.query.id, req.query.title);
        r.addThing(req.query.id, new Thing(req.query.id, req.query.title));
        res.send("Thing is added. Disconnection...");
        console.log(r.showThings());
    }
}

您能帮我找出错误吗？

Answer 1

您的构造函数将 this.things 定义为一个空对象，该对象没有定义函数 set。您需要初始化一个new Map():

things: Map

constructor() {
  this.things = new Map()
}