Angular: Is trackBy necessary with ngFor?

iterations: number = 1000;
dataPoints: number = 100000;
data: Array<any> = [];
startTime: Date;

constructor() {
  this.startTime = new Date();
  this.init();
}

init = (): void => {
  for (let i = 0, len = this.dataPoints; i < len; i++) {
    const datum: any = { index: i, identifier: this.makeid() };
    this.data.push(datum);
  }
};

makeid = (length: number = 50): string => {
  var result: string = '';
  var characters: string = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
  var charactersLength = characters.length;

  for ( var i = 0; i < length; i++ ) {
    result += characters.charAt(Math.floor(Math.random() * charactersLength));
  }

  return result;
};

getRandomInt = (min: number, max: number) => {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min + 1)) + min;
};

data: Array<any> = [];

constructor(
  private dataService: DataService
) { }

ngOnInit(): void {
  this.data = this.dataService.data;
  setTimeout(this.initiateReorganize.bind(this), 500);
}

ngAfterViewChecked(): void {
  const now: Date = new Date();
  const difference: number = now.getTime() - this.dataService.startTime.getTime();
  console.log('difference: ', difference);
}

identify = (index: number, item: any): string => item.index;

initiateReorganize = (): void => {
  const min: number = 0;
  const max: number = this.dataService.iterations - 1;
  for (let i = 0, len = this.dataService.iterations; i < len; i++) {
    const a: number = this.dataService.getRandomInt(min, max);
    const b: number = this.dataService.getRandomInt(min, max);
    [this.data[a], this.data[b]] = [this.data[b], this.data[a]];
  }
};

<div *ngFor="let item of data; trackBy: identify">
  {{ item.identifier }}
</div>