使用从firebase获取的对象数组，使用Angular2在下拉菜单中显示唯一选项

使用Angular2，我的html文件中有一个下拉菜单，如下所示（我使用Ink作为CSS框架）：

我的会员模式：

export class Member {
  public dateCreated: Date = new Date();
  public TWITTERPOPULATION: number = 328000000; // TODO figure of how to globally access this as a const
  public TOTALWORLDWEALTH: number = 60000000000;
  public influenceQuotient: number;

  constructor(public firstName: string, public lastName: string, public illuminatiNickname: string, public sectorOfInfluence: string, public numberOfTwitterFollowers: number, public netWorth: number, public politicalImpactQuotient: number, public suspicionOfIlluminatiMembership: number, public role: string, public salientDetails: string, public imgURL: string, public imgAlt: string) {
    this.influenceQuotient = numberOfTwitterFollowers/this.TWITTERPOPULATION + netWorth/this.TOTALWORLDWEALTH + politicalImpactQuotient - suspicionOfIlluminatiMembership;
  }
}

---

members[]只是一个成员对象数组（但从fireBase获取）。

您能否提供

members[]

结构？更新是否有帮助？什么是

members

？如果您尝试插入

async

管道，可能是

可观察的
？如何设置该属性，以及如何在“模板中的其他位置”使用该属性？请注意，删除重复项的方法不会将可观察的
作为输入或输出处理（因此异步管道将不工作，输入也不会工作）。如果原始源至少是一个
可观察的
，那么您可能希望在某个时间点对该源执行
.distinct（）
。如果你不能从这些笔记中找到答案，最好说明来源。谢谢，尼尔。是的，这是一个火箭筒。关于.distinct（）文档的任何线索？我不熟悉。
getUniqueRoles(members: Member[]){
    var flags = [], output = [], l = members.length, i;
    for( i=0; i<l; i++) {
      if( flags[members[i].role]) continue;
      flags[members[i].role] = true;
      output.push(members[i].role);
    }
    return output;
  }

export class Member {
  public dateCreated: Date = new Date();
  public TWITTERPOPULATION: number = 328000000; // TODO figure of how to globally access this as a const
  public TOTALWORLDWEALTH: number = 60000000000;
  public influenceQuotient: number;

  constructor(public firstName: string, public lastName: string, public illuminatiNickname: string, public sectorOfInfluence: string, public numberOfTwitterFollowers: number, public netWorth: number, public politicalImpactQuotient: number, public suspicionOfIlluminatiMembership: number, public role: string, public salientDetails: string, public imgURL: string, public imgAlt: string) {
    this.influenceQuotient = numberOfTwitterFollowers/this.TWITTERPOPULATION + netWorth/this.TOTALWORLDWEALTH + politicalImpactQuotient - suspicionOfIlluminatiMembership;
  }
}