Angular 5 - How to use a custom function within a class

I created a comment class, so i that i can refactor some code and add custom functions within the classes rather than having them all in my component. For example, a function for toggling Like/Dislike of a comment. However, when i create a simple custom function "hello" it does not work.

In my moment.component.ts i have a service which retrieves a "moment" object from my backend. I then use an ngFor in my app-moment-comment component to display each comment by passing in the current comment object. Here the moment is set to type any;

moment.component.ts

<app-moment-comment [comment]="comment" class="comment" *ngFor="let comment of moment?.comments></app-moment-comment>


comment.component.ts

export class MomentCommentComponent implements OnInit {

@Input() comment: Comment

constructor() { }

ngOnInit() {

this.comment.hello();

}


comment.model.ts

export class Comment {

_id: any;
body: any;
moment: any;
author: any;
likes: any;
dislikes: any;
parent: any;
replies: any;

constructor() {
console.log(this);
}


hello() {
console.log("hello")
}



}


When i call the hello() method, i get an error saying:

ERROR TypeError: this.comment.hello is not a function
​

Continue reading...