Filtering specific column in Angular Material table in angular 5 [duplicate]

Question

In Angular material official website it is mentioned that filterPredicate: ((data: T, filter: string) => boolean) will filter data based on specific field. But don't getting how to start.

I have seen example but not getting:-https://stackblitz.com/edit/angular-material2-table?file=app%2Fapp.component.html

By default it filter based on whole object but i want to search only based on single property of json.

Answer 1

Working filters on each column, demo link Stackblitz.

To filter specific column in mat-table, add a search field for the column as below;

<mat-form-field class="filter" floatLabel="never">
    <mat-label>Search</mat-label>
    <input matInput [formControl]="nameFilter">
  </mat-form-field>

And we connect the inputs to FormControls from the ReactiveFormsModule.

    filterValues = {
    name: '',
    id: '',
    colour: '',
    pet: ''
 };

And we will watch the value of the filter inputs and modify this filter object and the data source’s filter property when they change. We must assign the stringified version of the filter object to the data source’s filter property

    ngOnInit() {
    this.nameFilter.valueChanges
      .subscribe(
        name => {
          this.filterValues.name = name;
          this.dataSource.filter = JSON.stringify(this.filterValues);
        }
      )
    this.idFilter.valueChanges
      .subscribe(
        id => {
          this.filterValues.id = id;
          this.dataSource.filter = JSON.stringify(this.filterValues);
        }
      )
    this.colourFilter.valueChanges
      .subscribe(
        colour => {
          this.filterValues.colour = colour;
          this.dataSource.filter = JSON.stringify(this.filterValues);
        }
      )
    this.petFilter.valueChanges
      .subscribe(
        pet => {
          this.filterValues.pet = pet;
          this.dataSource.filter = JSON.stringify(this.filterValues);
        }
      )
  }

We have to change the data source’s filterPredicate to tell it how to interpret the filter information.

    constructor() {
    this.dataSource.data = this.people;
    this.dataSource.filterPredicate = this.tableFilter();
    }

    tableFilter(): (data: any, filter: string) => boolean {
    let filterFunction = function(data, filter): boolean {
      let searchTerms = JSON.parse(filter);
      return data.name.toLowerCase().indexOf(searchTerms.name) !== -1
        && data.id.toString().toLowerCase().indexOf(searchTerms.id) !== -1
        && data.colour.toLowerCase().indexOf(searchTerms.colour) !== -1
        && data.pet.toLowerCase().indexOf(searchTerms.pet) !== -1;
    }
    return filterFunction;
}
 

Answer 2

I managed to do like this:

this.dataSource.filterPredicate = (data, filter) =>
      (data.name.indexOf(filter) !== -1 ||
        data.id.indexOf(filter) !== -1 );
  }

Answer 3

Just declare a function with the following declaration in your component and then assign it to DataSource.filterPredicate. To use the filter just assign a string to DataSource.filter property.

  customFilter(Data: T, Filter: string): boolean {
    return <true if Data matches filter>
  }