custom filter in mat-table

Question

I\'m using mat-table. It has a filter which works fine with doc example:

From https://material.angular.io/components/table/overview, the original code is:

Answer 1

Be aware that all fields of the class displayed in table rows, are subject to filtering, even if you do not display that field as a column.

export class City {
  id: number;//is not displayed in mat table
  code: string;
  name: string;
  country:Country;
}

Any filter for the dataSource of city table, also applies to id column, which generally we do not display to the end user.

//this filter will also apply to id column
this.cityDataSource.filter = filterValue;