When working with Angular 2 and Typescript, a common error message that may be encountered is "TypeError

Question

When working with Angular 2 and Typescript, a common error message that may be encountered is "TypeError

Currently diving into Angular 2 and encountered a stumbling block while attempting to create a service. Despite my efforts in finding a solution, I seem to be missing something crucial.

Error:

A problem arises in angular2-polyfills.js:1243 with the error message stating that '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;        
    }
}

javascript angularjs typescript angular

Answer 1

Answer №1

Your code snippet demonstrates how to create a TweetService in Angular. However, it seems that your let statement is placed outside the class declarations, which may cause some issues. In a real application, you would likely be fetching the tweets from an API call.

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;        
    }
}

Answer 2

Your code snippet demonstrates how to create a TweetService in Angular. However, it seems that your let statement is placed outside the class declarations, which may cause some issues. In a real application, you would likely be fetching the tweets from an API call.

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;        
    }
}

When working with Angular 2 and Typescript, a common error message that may be encountered is "TypeError

Answer №1

Similar questions

What is the process for destructuring an interface in TypeScript?

Navigating to the HomePage using the nebular auth/login library with the login() function: A step-by-step guide

Angular - Set value on formArrayName

Ways to minimize an array using group by

Tips for separating these two words onto two separate lines

Angular error: Unable to access the 'toLowerCase' property of an undefined value

The Ajax request is not successfully communicating with the PHP script

What could be the reason for the undefined initial state in my vuex store?

Can Protractor effectively test AngularJS applications in an end-to-end manner?

Text in d3.js vanishing while undergoing rotation

Angular - Reacting to dynamically rendered content post-navigation

Testing Angular components that have protected @Input properties

Utilizing jQuery to correspond with CSS media queries

Incorporating a new method into the Object prototype to provide universal access across all modules

Upgrades in $q functionality during the transition from Angular 1.2.18 to version 1.4x

Angular: Assigning a key from one variable to a value in another

What are the strategies for distinguishing between languages in React Native prior to mounting the component?

How can I ensure that the ons-scroller stays at the bottom when writing a JavaScript code in Onsen UI?

What is the best way to extract the frameset from a frame window?

Once a WordPress user includes a php file