How to convert an object to JSON correctly in Angular 2 with TypeScript

I'm creating an Angular 2 simple CRUD application that allows me to CRUD products. I'm trying to implement the post method so I can create a product. My backend is an ASP.NET Web API. I'm having some trouble because when transforming my Product object to JSON it is not doing it correctly. The expected JSON should be like this:

{ "ID": 1, "Name": "Laptop", "Price": 2000
}

However, the JSON sent from my application is this:

{ "product":{ "Name":"Laptop", "Price":2000 }
}

Why is it adding a "product" in the beginning of the JSON? What can I do to fix this? My code:

product.ts

export class Product { constructor( public ID: number, public Name: string, public Price: number ) { }
}

product.service.ts

import {Injectable} from '@angular/core';
import {Http, Response} from '@angular/http';
import { Headers, RequestOptions } from '@angular/http';
import {Observable} from 'rxjs/Observable';
import {Product} from './product';
@Injectable()
export class ProductService { private productsUrl = ' constructor(private http: Http) { } getProducts(): Observable<Product[]> { return this.http.get(this.productsUrl) .map((response: Response) => <Product[]>response.json()) .catch(this.handleError); } addProduct(product: Product) { let body = JSON.stringify({ product }); let headers = new Headers({ 'Content-Type': 'application/json' }); let options = new RequestOptions({ headers: headers }); return this.http.post(this.productsUrl, body, options) .map(this.extractData) .catch(this.handleError); } private extractData(res: Response) { let body = res.json(); return body.data || {}; } private handleError(error: Response) { console.error(error); return Observable.throw(error.json().error || 'Server Error'); }
}

create-product.component.ts

import { Component, OnInit } from '@angular/core';
import { ROUTER_DIRECTIVES } from '@angular/router';
import { Product } from '../product'
import { ProductService } from '../product.service'
@Component({ moduleId: module.id, selector: 'app-create-product', templateUrl: 'create-product.html', styleUrls: ['create-product.css'],
})
export class CreateProductComponent { product = new Product(undefined, '', undefined); errorMessage: string; constructor(private productService: ProductService) { } addProduct() { if (!this.product) { return; } this.productService.addProduct(this.product) .subscribe( product => this.product, error => this.errorMessage = <any>error); }
}

create-product.html

<div> <h1>Create Product</h1> <form (ngSubmit)="addProduct()"> <div> <label for="name">Name</label> <input type="text" required [(ngModel)]="product.Name" name="Name" #name="ngModel"> </div> <div> <label for="Price">Price</label> <input type="text" required [(ngModel)]="product.Price" name="Price"> </div> <button type="submit" (click)="addProduct">Add Product</button> </form>
</div>

5 Answers

In your product.service.ts you are using stringify method in a wrong way..

Just use

JSON.stringify(product) 

instead of

JSON.stringify({product})

i have checked your problem and after this it's working absolutely fine.

You'll have to parse again if you want it in actual JSON:

JSON.parse(JSON.stringify(object))

If you are solely interested in outputting the JSON somewhere in your HTML, you could also use a pipe inside an interpolation. For example:

<p> {{ product | json }} </p>

I am not entirely sure it works for every AngularJS version, but it works perfectly in my Ionic App (which uses Angular 2+).

Because you're encapsulating the product again. Try to convert it like so:

let body = JSON.stringify(product); 

Tested and working in Angular 9.0

If you're getting the data using API

array: [];
ngOnInit() {
this.service.method()
.subscribe( data=> { this.array = JSON.parse(JSON.stringify(data.object)); }
)

}

You can use that array to print your results from API data in html template.

Like

<p>{{array['something']}}</p>