Use dependent facets

This is for:


Application developers often need to control the visibility of elements in a page, depending on some arbitrary condition.

In the context of a search application, a frequent use case is to define relationships between facets (or filters), so that a dependent facet will only appear when the user interacts with its specified parent facet.

Let’s assume that you have a @moviegenre facet field in your Coveo index, as well as a @moviesubgenre facet field.

@moviegenre may contain values such as Action, Comedy, or Drama.

@moviesubgenre may contain values such as War and Military Action, Martial Arts Action, Parody Comedy, or Historical Drama.

In your search interface, you only want the user to see the Movie genre facet initially. The Movie subgenre facet only appears after a selection is made in the Movie genre facet.

Defining the Relationship

The facet conditions manager lets you define dependencies to use when enabling a facet.

import { buildFacetConditionsManager } from "@coveo/headless";
import type {
} from "@coveo/headless";

function makeDependent(
  engine: SearchEngine,
  dependentFacet: Facet,
  parentFacets: Facet[]
) {
  const facetConditionsManager = buildFacetConditionsManager(engine, {
    facetId: dependentFacet.state.facetId,
    conditions: [ => {
        const parentFacetHasAnySelectedValueCondition: AnyFacetValuesCondition<FacetValueRequest> =
            parentFacetId: parentFacet.state.facetId,
            condition: (parentValues) =>
              parentValues.some((v) => v.state === "selected"),
        return parentFacetHasAnySelectedValueCondition;

  dependentFacet.subscribe(() => {

  addOnFacetDestroyedListener(dependentFacet.state.facetId, () => {

 * Show or hide the facet from the user.
function setFacetVisibility(facetId: string, shouldBeVisible: boolean) {
  // your code

 * Clean up a facet that we are no longer using. E.g.: when changing pages.
function addOnFacetDestroyedListener(facetId: string) {
  // your code

In the example above, the makeDependent function can be called to define a relationship between a dependent facet and one or more parent facets.

You can modify the condition function to fit your particular use case. For example, instead of verifying whether any value is selected (that is, equals selected) in the parent facet, you could verify the state of a specific value.

We don’t provide sample implementations for the setFacetVisibility and addOnFacetDestroyedListener functions, as they will vary depending on which Web framework you’re using (for example, Angular, React, or Vue).

React Example

To better understand this explanation, you can refer to this example made with React: Dependent Facet React Example.