instructor-list.component.ts

import {
  Component, Input, AfterViewInit,
  ChangeDetectionStrategy, ChangeDetectorRef
} from '@angular/core';

@Component({
  selector: 'app-instructor-list',
  templateUrl: './instructor-list.component.html',
  changeDetection: ChangeDetectionStrategy.OnPush
})
export class InstructorListComponent implements AfterViewInit {

  // Suppose this time the instructor list doesn't change after it arrives
  @Input() instructors = [];

  constructor(private cdr: ChangeDetectorRef) { }

  // Wait until the view inits before disconnecting
  ngAfterViewInit() {
    // Since we know the list is not going to change
    // let's request that this component not undergo change detection at all
    this.cdr.detach();
  }

  // Angular provides additional controls such as the following
  // if the situation allows

  // Request a single pass of change detection for the application
  // this.cdr.markForCheck();

  // Request a single pass of change detection for just this component
  // this.cdr.detectChanges();

  // Connect this component back to the change detection process
  // this.cdr.reattach();
}

this.crd.detach(); should be this.cdr.detach(); ;)

Fixed, thanks!

Welcome :)