Wrong directive 'ccFor'

[rbatllet]

The following directive is wrong: (angular2-sample-code/5.built-in-directives/6.structural-directives/script.ts)

@Directive({
  selector: '[ccFor]'
})
export class CodeCraftForOfDirective {
  constructor(private templateRef: TemplateRef<any>,
              private viewContainer: ViewContainerRef) {
  }

  @Input() set ccForOf(collection: any) {
    if (condition) {
      this.viewContainer.createEmbeddedView(this.templateRef);
    } else {
      this.viewContainer.clear();
    }
  }
}

The condition boolean variable is not defined.