Angular 2 / Typescript - TypeError: ClassName is not a constructor

Question

I am learning Angular 2 and I ran into this error while trying to create a service. I tried searching for a solution, but I cannot see my mistake.

Error:

angular2-polyfills.js:1243 TypeError: Tweet is not a constructor

Code:

export class TweetService{
    getTweets(){
        return tweets;
    }
}

let tweets = new Tweet("URL", "Author 1", "Handle 1", true, 50);

class Tweet {
    image: string;
    author: string;
    handle: string;
    status: "Lorem ipsum dolor sit amet.";
    isLiked: boolean;
    favorites: number;

    constructor(img, aut, hndl, ilkd, fav){
        img = this.image;
        aut = this.author;
        hndl = this.handle;
        ilkd = this.isLiked;
        fav = this.favorites;        
    }
}

I've check your code here typescriptlang.org/play and all compiles fine — Vasiliy vvscode Vanchuk
– Vasiliy vvscode Vanchuk, Commented May 28, 2016 at 10:09
Just clutching at straws here but did you try to export the Tweet class? — Oli
– Oli, Commented May 28, 2016 at 11:03
@Oli I don't think that is the problem. I tried it, but it didn't fix it. — Sir Rubberduck
– Sir Rubberduck, Commented May 28, 2016 at 11:12

FernOfTheAndes · Accepted Answer · 2016-05-28 13:01:24Z

2

Your let statement is floating outside the class declarations. This will work (but in an real app you would be setting your tweets based on some http call or something):

import {Injectable} from '@angular/core';

@Injectable()
export class TweetService{
    getTweets(){
        let tweets = new Tweet("URL", "Author 1", "Handle 1", true, 50);
        return tweets;
    }
}

class Tweet {
    image: string;
    author: string;
    handle: string;
    status: "Lorem ipsum dolor sit amet.";
    isLiked: boolean;
    favorites: number;

    constructor(img, aut, hndl, ilkd, fav){
        this.image = img;
        this.author = aut;
        this.handle = hndl;
        this.isLiked = ilkd;
        this.favorites = fav;        
    }
}

answered May 28, 2016 at 13:01

FernOfTheAndes

5,0152 gold badges20 silver badges25 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Sir Rubberduck Over a year ago

You are correct sir. This fixed the issue. About the http calls, I am currently learning Angular 2 and local repositories are more practical. Once I get better, I will use a RESTful API. Thank you.

Collectives™ on Stack Overflow

Angular 2 / Typescript - TypeError: ClassName is not a constructor

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related