Angular2无法从Observable对象访问子数组Object

Question

我的对象层次结构如下所示

export interface MandatoryTags {
    key: string;
    values: string[];
}

export interface Template {
    templateName: string;
    mTags: MandatoryTags[];

}

我试图从子接口访问数组。我收到错误Property＆＃39; mTags＆＃39;类型＆＃39;模板＆＃39;

上不存在

this.templateService.getTemplate(value).subscribe(res=>{

          this.selectedTemplate = res as Template;

            console.log(JSON.stringify(this.selectedTemplate)); //Works
            console.log(this.selectedTemplate.templateName);    //Works
    //      this.listOptions =  this.selectedTemplate.mTags; --> getting error :Property 'mTags' does not exist on type 'Template'

      }, err=>{
          console.log(err);
      });