---
product: "AG Grid"
title: "External Filter"
description: "External filtering allows custom filtering logic to be mixed with the grid's inbuilt filtering."
framework: angular
version: "36.2.0"
related:
    - title: "Overview"
      url: "https://www.ag-grid.com/archive/36.2.0/angular-data-grid/filtering-overview/"
    - title: "Column Filters"
      url: "https://www.ag-grid.com/archive/36.2.0/angular-data-grid/filtering/"
    - title: "Custom Column Filters"
      url: "https://www.ag-grid.com/archive/36.2.0/angular-data-grid/component-filter/"
    - title: "Floating Filters"
      url: "https://www.ag-grid.com/archive/36.2.0/angular-data-grid/floating-filters/"
    - title: "Custom Floating Filters"
      url: "https://www.ag-grid.com/archive/36.2.0/angular-data-grid/component-floating-filter/"
    - title: "Advanced Filter"
      url: "https://www.ag-grid.com/archive/36.2.0/angular-data-grid/filter-advanced/"
    - title: "Quick Filter"
      url: "https://www.ag-grid.com/archive/36.2.0/angular-data-grid/filter-quick/"
llms: "https://www.ag-grid.com/archive/36.2.0/llms.txt"
---

# External Filter

External filtering allows custom filtering logic to be mixed with the grid's inbuilt filtering.

> **Warning**
>
> This form of filtering is only compatible with the Client-Side Row Model, see [Row Models](https://www.ag-grid.com/archive/36.2.0/angular-data-grid/row-models/) for more details.

#### External Filter

```ts
import { Component, type OnInit, computed, signal } from "@angular/core";

import { AgGridAngular } from "ag-grid-angular";
import type { ColDef, IDateFilterParams, IRowNode } from "ag-grid-community";
import {
  ClientSideRowModelModule,
  DateFilterModule,
  ExternalFilterModule,
  ModuleRegistry,
  NumberFilterModule,
  enableDevValidations,
} from "ag-grid-community";
import {
  ColumnMenuModule,
  ColumnsToolPanelModule,
  ContextMenuModule,
  SetFilterModule,
} from "ag-grid-enterprise";

import type { IOlympicData } from "./interfaces";
import "./styles.css";

if (process.env.NODE_ENV !== "production") {
  // Enable extended validations only for development
  enableDevValidations();
}

ModuleRegistry.registerModules([
  ExternalFilterModule,
  ClientSideRowModelModule,
  ColumnsToolPanelModule,
  ColumnMenuModule,
  ContextMenuModule,
  SetFilterModule,
  NumberFilterModule,
  DateFilterModule,
]);

@Component({
  standalone: true,
  imports: [AgGridAngular],
  selector: "my-app",
  template: `
    <div class="test-container">
      <div class="test-header">
        <label>
          <input
            type="radio"
            name="filter"
            id="everyone"
            checked
            (change)="onAgeTypeChanged('everyone')"
          />
          Everyone
        </label>
        <label>
          <input
            type="radio"
            name="filter"
            id="below25"
            (change)="onAgeTypeChanged('below25')"
          />
          Below 25
        </label>
        <label>
          <input
            type="radio"
            name="filter"
            id="between25and50"
            (change)="onAgeTypeChanged('between25and50')"
          />
          Between 25 and 50
        </label>
        <label>
          <input
            type="radio"
            name="filter"
            id="above50"
            (change)="onAgeTypeChanged('above50')"
          />
          Above 50
        </label>
        <label>
          <input
            type="radio"
            name="filter"
            id="dateAfter2008"
            (change)="onAgeTypeChanged('dateAfter2008')"
          />
          After 01/01/2008
        </label>
      </div>
      <ag-grid-angular
        style="width: 100%; height: 100%;"
        [columnDefs]="columnDefs"
        [defaultColDef]="defaultColDef"
        [rowData]="rowData()"
        [isExternalFilterPresent]="isExternalFilterPresent()"
        [doesExternalFilterPass]="doesExternalFilterPass()"
      />
    </div>
  `,
})
export class AppComponent implements OnInit {
  public ageType = signal("everyone");
  public rowData = signal<IOlympicData[] | null>(null);

  public dateFilterParams: IDateFilterParams = {
    comparator: (filterLocalDateAtMidnight: Date, cellValue: string) => {
      const cellDate = this.asDate(cellValue);

      if (filterLocalDateAtMidnight.getTime() === cellDate.getTime()) {
        return 0;
      }
      if (cellDate < filterLocalDateAtMidnight) {
        return -1;
      }
      if (cellDate > filterLocalDateAtMidnight) {
        return 1;
      }
      return 0;
    },
  };

  public columnDefs: ColDef<IOlympicData>[] = [
    { field: "athlete", minWidth: 180 },
    { field: "age", filter: "agNumberColumnFilter" },
    { field: "country" },
    { field: "year" },
    {
      field: "date",
      filter: "agDateColumnFilter",
      filterParams: this.dateFilterParams,
    },
    { field: "total", filter: "agNumberColumnFilter" },
  ];

  public defaultColDef: ColDef = {
    flex: 1,
    minWidth: 120,
    filter: true,
  };

  // Each computed produces a new function reference whenever ageType changes, and the grid
  // re-runs external filtering as soon as it is given one.
  public isExternalFilterPresent = computed(() => {
    const ageType = this.ageType();
    return (): boolean => ageType !== "everyone";
  });

  public doesExternalFilterPass = computed(() => {
    const ageType = this.ageType();
    return (node: IRowNode<IOlympicData>): boolean => {
      if (node.data) {
        switch (ageType) {
          case "below25":
            return node.data.age < 25;
          case "between25and50":
            return node.data.age >= 25 && node.data.age <= 50;
          case "above50":
            return node.data.age > 50;
          case "dateAfter2008":
            return this.asDate(node.data.date) > new Date(2008, 0, 1);
          default:
            return true;
        }
      }
      return true;
    };
  });

  public ngOnInit() {
    fetch("https://www.ag-grid.com/example-assets/olympic-winners.json")
      .then((response) => response.json())
      .then((data: IOlympicData[]) => this.rowData.set(data));
  }

  public onAgeTypeChanged(newValue: string) {
    this.ageType.set(newValue);
  }

  private asDate(dateAsString: string): Date {
    const splitFields = dateAsString.split("/");
    return new Date(
      Number.parseInt(splitFields[2]),
      Number.parseInt(splitFields[1]) - 1,
      Number.parseInt(splitFields[0]),
    );
  }
}
```

[Live example: External Filter](https://www.ag-grid.com/archive/36.2.0/examples/filter-external/external-filter/angular/)

## Implementing External Filtering

The example above shows external filters in action. Two methods on `gridOptions` are required to be implemented: `isExternalFilterPresent` and `doesExternalFilterPass`.

| Property | Type | Required | Default | Description |
| --- | --- | --- | --- | --- |
| `isExternalFilterPresent` | `IsExternalFilterPresent` |  |  |  |
| `doesExternalFilterPass` | `DoesExternalFilterPass` |  |  |  |

## Re-running the External Filter

The filter state is held outside the grid, so the grid has to be told when that state has changed. Pick one of the following approaches:

- [Calling onFilterChanged](https://www.ag-grid.com/archive/36.2.0/angular-data-grid/filter-external/#calling-onfilterchanged) - the callback references are kept stable and the filter is re-run only when the API is called.
- [Supplying New Callbacks](https://www.ag-grid.com/archive/36.2.0/angular-data-grid/filter-external/#supplying-new-callbacks) - a new callback reference is handed to the grid and the filter is re-run automatically.

### Calling onFilterChanged

After the filter state has changed call `api.onFilterChanged()` to ask the grid to run filtering again.

| Property | Type | Required | Default | Description |
| --- | --- | --- | --- | --- |
| `onFilterChanged` | `FilterChangedEventSourceType` |  |  |  |

```js
// Filter state updated now re-run filtering
api.onFilterChanged();
```

Ensure the callbacks have stable references to avoid triggering filtering excessively.

> **Warning**
>
> A template binding is re-evaluated on every change-detection run, and `.bind(this)` returns a new function each time it is evaluated so the grid re-filters on every cycle:
>
> ```html
> <ag-grid-angular [isExternalFilterPresent]="isExternalFilterPresent.bind(this)" />
> ```
>
> Prefer an arrow function defined on the component instead as the reference is stable for the lifetime of the component.

### Supplying New Callbacks

`isExternalFilterPresent` and `doesExternalFilterPass` are reactive grid properties, so replacing either one with a new function re-runs filtering automatically.

Where the filter state is held in a signal, each callback is exposed as a `computed` that returns the filter function, and the invoked signal is bound in the template. A change to the state signal recomputes the callback, so the grid is given a new reference and re-runs filtering:

```ts
@Component({
    template: `<ag-grid-angular [doesExternalFilterPass]="doesExternalFilterPass()" />`,
})
export class AppComponent {
    public minAge = signal(0);

    public doesExternalFilterPass = computed(() => {
        const minAge = this.minAge();
        return (node: IRowNode<IOlympicData>) => node.data!.age > minAge;
    });
}
```

The state signal is read outside the returned function so that it is a dependency of the `computed`. Reading it inside the returned function instead leaves the `computed` with no dependencies, and the reference never changes.

Reassigning a plain class field hands the grid a new reference in the same way:

```ts
// reassigning the field hands the grid a new reference, and filtering re-runs
this.doesExternalFilterPass = (node: IRowNode<IOlympicData>) => node.data!.age > this.minAge;
```

The example on this page takes the second path: `ageType` is a signal, and both callbacks are `computed` values that read it.