Clash Royale CLAN TAG#URR8PPP

ERROR TypeError: Cannot set property 'author' of undefined

I get this error when i want to save changes to sever " add a comment" by clicking Submit button thanks for helping

onSubmit()
this.comment.author = this.author;
this.comment.rating = this.rating;
this.comment.comment = this.comment1;


this.comment.date = new Date().toISOString();
console.log(this.comment);
this.dishcopy.comments.push(this.comment);
this.dishcopy.save()
.subscribe(dish => this.dish = dish; console.log(this.dish); );




template code:

<div class="example-container">
<mat-form-field>
<input matInput placeholder="author" [(ngModel)]="author">
</mat-form-field>
<mat-form-field>
<mat-select placeholder="rating" [(ngModel)]='rating'>
<mat-option value="1">1</mat-option>
<mat-option value="2">2</mat-option>
<mat-option value="3">3</mat-option>
<mat-option value="4">4</mat-option>
<mat-option value="5">5</mat-option>
</mat-select>
</mat-form-field>
<mat-form-field>
<textarea matInput placeholder="comment" [(ngModel)]="comment1"></textarea>
</mat-form-field>
<button (click)="onSubmit()">Submit</button>
</div>


More deteils:
this is Comment.ts code:

export class Comment
rating: number;
comment: string;
author: string;
date: string;


and I instantiate it by:

import Comment from '../shared/comment';
...
comment:Comment;


1 Answer
1

It seems that you have never instantiated this.comment, so when you try to access its author property you find it undefined.

this.comment

author

add this code to the beginning of onSubmit()

onSubmit()

this.comment = new Comment();


Keep in mind that if you don't need some checks or logic operations into onSubmit() you could bind directly this.comment's properties to template variables

onSubmit()

this.comment

EDIT

This code comment:Comment; is not an instantiation, is
a declaration. You need this:

comment:Comment;

comment: Comment = new Comment();


or this by letting TypeScript infer the type:

comment = new Comment();


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