错误类型错误:无法在搜索函数处读取未定义的属性“slice”-角度2+

我有一个 angular5-data-table 我正在实现的模块。我可以使用它的所有功能。另外,我想在上面添加一个搜索功能。我添加了下面的代码(html和typescript)并开始接收 ERROR TypeError: Cannot read property 'slice' of undefined 错误。

我的搜索HTML是:

<input type="text" class="form-control input-md" placeholder="Search by full name" #query (keyup)="searchMember(query.value)" [(ngModel)]="filter.name">

这背后的密码 searchMember(query.value) 是:

searchMember(query: string) {
  let members = this.allMembers;
  if (this.filter.firstName) {
    members = members.filter(o => o.firstName.toLowerCase().includes(query.toLowerCase()));
 }
  this.members = members;
  this.initializeTable(this.members);
  console.log(members);
}

这里是 initializeTable() :

  private initializeTable(members: Member[]) {
    this.tableResource = new DataTableResource(members);
    this.tableResource.query({ offset: 0 }).then(items => this.items = items);
    this.tableResource.count().then(count => this.itemCount = count);
 }

最后,这里是初始化:

filter: any = {};
tableResource: DataTableResource<Member>;
allMembers: Member[];

我不确定我是否理解这个错误。有什么想法吗?