how to create "ngOnActive" life cycle hook in angular?

I want a life cycle hook to be called when ever my component is active on the main page.

its login page.

when ever my component is on the main page i.e is active i want to see if i already have login token from previous login and depending on the result i want to navigate to different page.

is there any `ngOnActive' hook if not then how to create it?

or is there is any other way to achieve this?

my code:

import { Component, OnInit } from '@angular/core';
import { NgForm } from '@angular/forms';
import {LoginService} from './login.service';
import {TokenService} from '../data/token.service';
import {Router} from '@angular/router';

@Component({
  selector: 'app-login',
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.css'],
  providers: [LoginService]
})
export class LoginComponent implements OnInit {

  constructor(private loginService: LoginService, private tokenService: TokenService, private router: Router) { }

  ngOnInit() {
    if (this.tokenService.getToken() !== '') {
      console.log(this.tokenService.tk);
      this.router.navigate(['/admin']);
    }
  }
  onSubmit(form: NgForm) {
    this.loginService.login(form.value.email, form.value.password);
  }
}

Here is a piece of code that will serve as an example:

(function () {
  angular.module('app', [])
    .controller('MainController', function() {
      activate();
      function activate() {
        console.log('Success'); // this log will appear when ever your controller loads
      }
    });
})();