Angular4 - post form data to rest api

Ok, so it turns out i have to add .subscribe() to post for it to do something. Also if i put "user" straight into post request for some reason it sends an request with method "OPTIONS" without a body. So i have to create a queryParams string myself. If anyone can explain this or show a better way to do this i would appriciate it. Otherwise this currently works:

 onSubmit = function (user) {
    console.log(user);

    var body = "firstname=" + user.firstname + "&lastname=" + user.lastname + "&name=" + user.name;
    this.http.post("http://www.testtttt.com", body).subscribe((data) => {});

  }

Edit: another and probably even a better solution is to use JSON.stringify(user) instead of body. But subscribe() is still needed tho.

For Making as generic Post & Get Method in angular 2/4 using form data

import { Http, Response, Headers, RequestOptions } from '@angular/http'; 
import { Observable } from 'rxjs/Observable';

constructor(private _http: Http) { }

get(url: string): Observable < any > {
    return this._http.get(url)
             .map((response: Response) => <any>response.json()); 
}

post(url: string, model: any): Observable <any> {
    let formData: FormData = new FormData(); 
    formData.append('id', model.id); 
    formData.append('applicationName', model.applicationName); 
    return this._http.post(url, formData)
        .map((response: Response) => {
            return response;
        }).catch(this.handleError); 
}

How about using Typescript to make your life easier?

The html has ngModel two way binding.I've changed to rename the form personForm. You can add validation, but I have skipped it here.

 <form #personForm="ngForm"(ngSubmit)="onSubmit(personForm.value)">     
  <input name="firstName" [(ngModel)]="firstName">
  <input name="lastName" [(ngModel)]="lastName">
  <button type="submit">Save</button>
 </form>

On the component, you can use an interface Person which you can define in a models folder. The contents looks like this.

export interface Person {
  id:number;
  firstName: string;
  lastName: string;
}

And then in the submit method you can map it automatically like below.

onSubmit(person: Person){
  http.post('your_url', person).subscribe(status=> console.log(JSON.stringify(status)));
}

See how easy it is type safety? Also you can check if id is populated and either make a 'PUT' or 'DELETE' request depending on whether you want to update the person or delete.

Let me contribute to the accepted answer since I don't have enough reputation to comment. Rather than pick all the form inputS one by one into a model, you could do the following

var model = this.forContollname.value

Then you could call the following

 var values = JSON.stringify(model)

The values can then be passed into your post method. I hope this simplifies the process for someone with a large form.