Angular 5/6 method to handle Campaign Monitor's secure subscribe link signup

app.component.html

<form [formGroup]="subForm" (ngSubmit)="submitsubForm()">
	<mat-form-field>
		<input matInput type="text" name="email" placeholder="Email Address" formControlName="emailFormControl">
	</mat-form-field>
	<button mat-flat-button>Submit</button>
</form>

app.component.ts

import { FormControl, Validators } from '@angular/forms';

export class AppComponent implements {
	cm_id = '';
	cm_emailfield = 'cm-';
	subForm = new FormGroup({
		emailFormControl: new FormControl('', [ Validators.required, Validators.email ])
	});

	submitsubForm(): void {
		let subdata = {
			'email' : this.subForm.controls.emailFormControl.value,
			'data' : this.cm_id
		};
		// Get secure subscribe URL from Campaign Monitor
		this.apiService.campaignMonitorToken(subdata)
		.subscribe( token => {
			console.log(token);
			// Subscribe user with new secure subscribe URL from Campaign Monitor
			this.apiService.campaignMonitorSub(token, this.subForm.controls.emailFormControl.value, this.cm_emailfield)
			.subscribe( result => {
				console.log(result);
			});
		});
	}
	
}

cm.service.ts

import { Injectable } from '@angular/core';
import { HttpClient, HttpParams } from '@angular/common/http';
import { HttpHeaders } from '@angular/common/http';

import { Observable,  of } from 'rxjs';
import { catchError } from 'rxjs/operators';

import { HttpErrorHandler, HandleError } from '../http-error-handler.service';

const httpOptions = {
  headers: new HttpHeaders({
    'Content-Type': 'application/json',
    'Authorization': 'lgc-auth-token'
  })
};

@Injectable()
export class ApiService {
  private handleError: HandleError;

  constructor(
    private http: HttpClient,
    httpErrorHandler: HttpErrorHandler) {
    this.handleError = httpErrorHandler.createHandleError('ApiService');
  }

  /** Campaign Monitor Get Token */
  campaignMonitorToken (data): Observable<any> {
    return this.http.post('https://createsend.com//t/getsecuresubscribelink', `email=${data.email}&data=${data.data}`, { headers: new HttpHeaders({ 'Content-Type': 'application/x-www-form-urlencoded'}), responseType: 'text'})
      .pipe(
        catchError(this.handleError('campaignMonitorToken', data))
      );
  }

  /** Campaign Monitor Add Subscriber */
  campaignMonitorSub (secureUrl, email, emailfield): Observable<any> {
    return this.http.post(secureUrl, `${emailfield}=${email}`, { headers: new HttpHeaders({ 'Content-Type': 'application/x-www-form-urlencoded'}), responseType: 'text'})
      .pipe(
        catchError(this.handleError('campaignMonitorSub', email))
      );
  }
}