if-feature-flag.live-updates.ts

import { Directive, Input, TemplateRef } from '@angular/core';

@Directive({
  selector: '[ifFeature]',
})
export class IfFeatureFlagDirective<IfTemplate, ElseTemplate> {
  constructedForFlag?: string;
  elseTemplate?: TemplateRef<ElseTemplate>;
  flag?: string;

  @Input('ifFeature')
  set ifFeatureFlag(flag: string) {
    this.flag = flag;
    this.updateView();
  }

  @Input('ifFeatureElse')
  set ifFeatureFlagNotPresent(t: TemplateRef<ElseTemplate>) {
    this.elseTemplate = t;
  }

  private updateView() {
    this.flags.checkIsOn(this.flag).subscribe((on) => {
      this.viewContainerRef.clear();
      if (on) {
        this.viewContainerRef.createEmbeddedView(this.template);
      } else if (this.elseTemplate != null) {
        this.viewContainerRef.createEmbeddedView(this.elseTemplate);
      } else {
        this.viewContainerRef.clear();
      }
    });
  }
}