如何将Angular 6 POST值发送到Codeigniter功能？

Here is the

registration.component.ts

registrationDetails(event) {

const target = event.target;
const app_key = 'a9a4a7757d840aa317bb585f4acbdf0d';
const first_name = target.querySelector("#firstname").value;
const last_name = target.querySelector("#lastname").value;
const email = target.querySelector("#username").value;
const password = target.querySelector("#password").value;
const phone = target.querySelector("#phone_number").value;
this.Auth.postRegistration(first_name, last_name, email, password,phone,app_key).subscribe(
  data => {
    if ((data.status == 1)) {
      this.toastr.success('Registartion Successfull, Please login', "Thank you..!");
    } else {
      this.toastr.error(data.response, "OOPS..!");
    }
  }
);   }

and Here is the

auth.service.ts

postRegistration(first_name, last_name, email, password,phone,app_key) {
    return this.Http.post<objects>(`${this.baseUrl}/user/registerUser`, {
      first_name,
      last_name,
      email,
      phone,
      password,
      app_key
    });

when am running this file the posting values are not going to Codeigniter function what is the problem in this and what are changes should be done, actually core php works $_POST['email'] but $this->input->post('email') this is not working why ?

here you are passing raw data

so try this

postRegistration(first_name, last_name, email, password,phone,app_key) {
    const header = new HttpHeaders().set('Content-Type', 'application/x-www-form-urlencoded')
    let body = 'first_name='+first_name+'&last_name='+last_name+'&email='+email+'&phone='+phone+'&password='+password+'&app_key='+app_key;
    return this.Http.post<objects>(`${this.baseUrl}/user/registerUser`, body, {headers: header});
}