Ember.js Route addObserver() Method

import Component from '@glimmer/component';
import Ember from 'ember';
import { tracked } from '@glimmer/tracking';
import { action, addObjects, set, get } from '@ember/object';
export default Ember.Component.extend({
    value: 'Oxygen',
    init() {
        this._super(...arguments);
        this.addObserver('value', this, 'change');
        alert('Route Init() is initiated');
    },
    change() {
        console.log('Value changed ')
    },
    p1: [
        'Oxygen',
        'Source Code',
        'Infinite',
        'Tenet',
        'SpiderHead',
        'The Thing',
        'A Quiet Place',
        'The Invisible Man',
        'Looper',
        'Ad Astra',
    ],
  

  @action
remove(data) {
    this.p1.set('[]', this.p1.without(data));
},
@action
print(){
    let ans = this.p1.get('[]');
    alert(ans.join('\n'))
}

})

import Component from '@glimmer/component';
import { tracked } from '@glimmer/tracking';
import { action } from '@ember/object';
import { mapBy } from '@ember/object';
import Ember from 'ember';
let Student = Ember.Object.extend({
    // these will be supplied by `create`
    firstName: null,
    lastName: null,
    fullName: Ember.computed('firstName', 'lastName', function () {
        return `${this.firstName} ${this.lastName}`;
    }),

    Changed: Ember.observer('fullName', function () {
        console.log(`fullName changed to: ${this.fullName}`);
    }),
});

export default Ember.Component.extend({
    students: [
        Student.create({
            firstName: 'Kasual',
            lastName: 'Singh',
            Id: 'stu2',
        }),
        Student.create({
            firstName: 'Yehuda',
            lastName: 'Katz',
            Id: 'stu0',
        }),
        Student.create({
            firstName: 'Yella',
            lastName: 'melo',
            Id: 'stu1',
        }),
        Student.create({
            firstName: 'Pokhu',
            lastName: 'Verma',
            Id: 'stu3',
        })], 
  @tracked
value: 'Pokhu',

  @tracked
value2: 'Pokhraj',

  @action
print(data1, data2) {
    let ans = this.students.find((item) => 
        item.get('firstName') == data1)
    ans.set('lastName', data2)
}
})