Angular 2 declaring an array of objects

Question

I have the following expression:

public mySentences:Array = [
    {id: 1, text: \'Sentence 1\'},
    {id: 2, text: \'Sentence 2\'},
    {id: 3,         


        

Answer 1

public mySentences:Array<any> = [
    {id: 1, text: 'Sentence 1'},
    {id: 2, text: 'Sentence 2'},
    {id: 3, text: 'Sentence 3'},
    {id: 4, text: 'Sentenc4 '},
];

OR

public mySentences:Array<object> = [
    {id: 1, text: 'Sentence 1'},
    {id: 2, text: 'Sentence 2'},
    {id: 3, text: 'Sentence 3'},
    {id: 4, text: 'Sentenc4 '},
];

Answer 2

Datatype: array_name:datatype[]=[]; Example string: users:string[]=[];

For array of objects:

Objecttype: object_name:objecttype[]=[{}]; Example user: Users:user[]=[{}];

And if in some cases it's coming undefined in binding, make sure to initialize it on Oninit().

Answer 3

I assume you're using typescript.

To be extra cautious you can define your type as an array of objects that need to match certain interface:

type MyArrayType = Array<{id: number, text: string}>;

const arr: MyArrayType = [
    {id: 1, text: 'Sentence 1'},
    {id: 2, text: 'Sentence 2'},
    {id: 3, text: 'Sentence 3'},
    {id: 4, text: 'Sentenc4 '},
];

Or short syntax without defining a custom type:

const arr: Array<{id: number, text: string}> = [...];

Answer 4

First, generate an Interface

Assuming you are using TypeScript & Angular CLI, you can generate one by using the following command

ng g interface car

After that set the data types of its properties

// car.interface.ts
export interface car {
  id: number;
  eco: boolean;
  wheels: number;
  name: string;
}

You can now import your interface in the class that you want.

import {car} from "app/interfaces/car.interface";

And update the collection/array of car objects by pushing items in the array.

this.car.push({
  id: 12345,
  eco: true,
  wheels: 4,
  name: 'Tesla Model S',
});

More on interfaces:

An interface is a TypeScript artifact, it is not part of ECMAScript. An interface is a way to define a contract on a function with respect to the arguments and their type. Along with functions, an interface can also be used with a Class as well to define custom types. An interface is an abstract type, it does not contain any code as a class does. It only defines the 'signature' or shape of an API. During transpilation, an interface will not generate any code, it is only used by Typescript for type checking during development. - https://angular-2-training-book.rangle.io/handout/features/interfaces.html

Answer 5

type NumberArray = Array<{id: number, text: string}>;

const arr: NumberArray = [
    {id: 0, text: 'Number 0'},
    {id: 1, text: 'Number 1'},
    {id: 2, text: 'Number 2'},
    {id: 3, text: 'Number 3 '},
    {id: 4, text: 'Number 4 '},
    {id: 5, text: 'Number 5 '},
];

Answer 6

public mySentences:Array<Object> = [
    {id: 1, text: 'Sentence 1'},
    {id: 2, text: 'Sentence 2'},
    {id: 3, text: 'Sentence 3'},
    {id: 4, text: 'Sentenc4 '},
];

Or rather,

export interface type{
    id:number;
    text:string;
}

public mySentences:type[] = [
    {id: 1, text: 'Sentence 1'},
    {id: 2, text: 'Sentence 2'},
    {id: 3, text: 'Sentence 3'},
    {id: 4, text: 'Sentenc4 '},
];