Angular: error in model with object listing

I have these 2 models, and the book has a list of language type objects.

Model book
import { Language} from "./language";
export class Book {
    id: number;
    name: string;
    language: Array<Language>;
}

Model language
export class Language{
    id: number;
    name: string;
}

Quando tento criar o objeto livro e adicionar uma linguagem na sua listagem de linguagens, tenho erro de undefined:

myBook: Book();
myLanguage: Language();

hello() {
    this.myLanguage = new Language();
    this.myLanguage.id = 1;
    this.myLanguage.name = "portuguese";

    this.myBook = new Book();
    this.myBook.id = 1;
    this.myBook.name = "one book";
    this.myBook.language.push(this.myLanguage); //error - undefined
}
Would

Need some different kind of statement for this listing?

Thank you.

Author: Sivy, 2018-12-27
Source

1 answers

Before push, associate an empty array to language: 

this.myBook.language = [];
this.myBook.language.push(this.myLanguage);
 3
Author: Renata, 2018-12-27 17:20:00