Class FeatureFlagReader

Firebase-backed reader for feature flags, segments, and conditions.

This class provides methods to fetch and subscribe to feature flag data from Firestore. it handles workspace fallbacks (global vs specific) and maintains an internal cache for performance.

Example

const reader = new FeatureFlagReader({
  db: firestoreInstance,
  workspace: 'production',
  userContext: { userId: 'user-123' }
});

const isEnabled = await reader.getFeatureFlag('new_feature').then(f => f?.getIsEnabled());

Hierarchy (View Summary)

FeatureReader
- FeatureFlagReader

Constructors

constructor

new FeatureFlagReader(options: IFeatureFlagReaderOptions): FeatureFlagReader
Creates a new FeatureReader instance.
Parameters
- options: IFeatureFlagReaderOptions
  Configuration options including Firestore instance, workspace, and optional user context
Returns FeatureFlagReader
Overrides FeatureReader.constructor
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:77

Properties

`Protected` `Readonly`db

db: FirestoreDb

`Protected`prefetchPromise

prefetchPromise: Promise<unknown> | null = null

`Static`Feature

Feature: typeof Feature = Feature

Methods

getAllFeatureConditions

getAllFeatureConditions(): Promise<Record<string, FeatureCondition> | null>
Returns Promise<Record<string, FeatureCondition> | null>
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:223

getAllSegmentGroups

getAllSegmentGroups(): Promise<Record<string, ISegmentGroupClass> | null>
Returns Promise<Record<string, ISegmentGroupClass> | null>
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:207

getFeatureCondition

getFeatureCondition(conditionName: string): Promise<FeatureCondition | null>
Fetches a named feature condition.
Parameters
- conditionName: string
  The name of the condition
Returns Promise<FeatureCondition | null>
The feature condition logic, or null if not found
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:159

getFeatureFlag

getFeatureFlag(flagName: string): Promise<Feature | null>
Fetches a single feature flag by name.
Parameters
- flagName: string
  The unique name of the feature flag
Returns Promise<Feature | null>
A Feature instance for evaluation, or null if not found
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:114

getFeatureFlagArchived

getFeatureFlagArchived(flagName: string): Promise<Feature | null>
Fetches a single archived feature flag.
Parameters
- flagName: string
  The unique name of the archived feature flag
Returns Promise<Feature | null>
A Feature instance, or null if not found
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:129

getFeatureFlags

getFeatureFlags(): Promise<Record<string, Feature> | null>
Fetches all active feature flags in the current workspace.

Returns Promise<Record<string, Feature> | null>
A record of flag names to Feature instances
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:175

getFeatureFlagsArchived

getFeatureFlagsArchived(
__namedParameters: { useCache: boolean },
): Promise<Record<string, Feature> | null>
Parameters
- __namedParameters: { useCache: boolean }
Returns Promise<Record<string, Feature> | null>
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:189

getSegmentGroup

getSegmentGroup(segmentName: string): Promise<SegmentGroup | null>
Fetches a segment group by name.
Parameters
- segmentName: string
  The name of the segment
Returns Promise<SegmentGroup | null>
A SegmentGroup instance, or null if not found
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:144

`Protected`safeFetch

safeFetch<T, D>(
    collection: string,
    docName: string,
    factory: (key: string, data: D) => T,
    cache: Map<string, D>,
): Promise<T | null>
Type Parameters
- T
- D
Parameters
- collection: string
- docName: string
- factory: (key: string, data: D) => T
- cache: Map<string, D>
Returns Promise<T | null>
Inherited from FeatureReader.safeFetch
- Defined in adapters/firebase-adapter/src/feature-reader.ts:22

`Protected`safeFetchAll

safeFetchAll<T, D>(
    collection: string,
    factory: (key: string, data: D) => T,
    cache: Map<string, D>,
    allLoaded: boolean,
    useCache?: boolean,
): Promise<Record<string, T> | null>
Type Parameters
- T
- D
Parameters
- collection: string
- factory: (key: string, data: D) => T
- cache: Map<string, D>
- allLoaded: boolean
- useCache: boolean = true
Returns Promise<Record<string, T> | null>
Inherited from FeatureReader.safeFetchAll
- Defined in adapters/firebase-adapter/src/feature-reader.ts:44

subscribeToAllFeatureConditons

subscribeToAllFeatureConditons(
onChange: (groups: Record<string, FeatureCondition>) => void,
onError?: (error: Error) => void,
): Unsubscribe
Parameters
- onChange: (groups: Record<string, FeatureCondition>) => void
- OptionalonError: (error: Error) => void
Returns Unsubscribe
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:304

subscribeToAllSegmentGroups

subscribeToAllSegmentGroups(
onChange: (groups: Record<string, SegmentGroup>) => void,
onError?: (error: Error) => void,
): Unsubscribe
Parameters
- onChange: (groups: Record<string, SegmentGroup>) => void
- OptionalonError: (error: Error) => void
Returns Unsubscribe
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:338

subscribeToFeatureConditon

subscribeToFeatureConditon(
    conditionName: string,
    onChange: (conditon: FeatureCondition | null) => void,
    onError?: (error: Error) => void,
): Unsubscribe
Parameters
- conditionName: string
- onChange: (conditon: FeatureCondition | null) => void
- OptionalonError: (error: Error) => void
Returns Unsubscribe
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:289

subscribeToFeatureFlag

subscribeToFeatureFlag(
    flagName: string,
    onChange: (feature: Feature | null) => void,
    onError?: (error: Error) => void,
): Unsubscribe
Subscribes to real-time updates for a single feature flag.
Parameters
- flagName: string
  Name of the flag to watch
- onChange: (feature: Feature | null) => void
  Callback triggered when the flag data changes
- OptionalonError: (error: Error) => void
  Optional error callback
Returns Unsubscribe
Unsubscribe function
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:247

subscribeToFeatureFlags

subscribeToFeatureFlags(
onChange: (features: Record<string, Feature>) => void,
onError?: (error: Error) => void,
): Unsubscribe
Subscribes to real-time updates for all feature flags in the workspace.
Parameters
- onChange: (features: Record<string, Feature>) => void
  Callback triggered when any flag in the collection changes
- OptionalonError: (error: Error) => void
  Optional error callback
Returns Unsubscribe
Unsubscribe function
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:271

subscribeToSegmentGroup

subscribeToSegmentGroup(
    segmentName: string,
    onChange: (segmentGroup: SegmentGroup | null) => void,
    onError?: (error: Error) => void,
): Unsubscribe
Parameters
- segmentName: string
- onChange: (segmentGroup: SegmentGroup | null) => void
- OptionalonError: (error: Error) => void
Returns Unsubscribe
- Defined in adapters/firebase-adapter/src/feature-flag-reader.ts:321

Class FeatureFlagReader

Example

Hierarchy (View Summary)

Index

Constructors

Properties

Methods

Constructors

constructor

Parameters

Returns FeatureFlagReader

Properties

Protected Readonlydb

ProtectedprefetchPromise

StaticFeature

Methods

getAllFeatureConditions

Returns Promise<Record<string, FeatureCondition> | null>

getAllSegmentGroups

Returns Promise<Record<string, ISegmentGroupClass> | null>

getFeatureCondition

Parameters

Returns Promise<FeatureCondition | null>

getFeatureFlag

Parameters

Returns Promise<Feature | null>

getFeatureFlagArchived

Parameters

Returns Promise<Feature | null>

getFeatureFlags

Returns Promise<Record<string, Feature> | null>

getFeatureFlagsArchived

Parameters

Returns Promise<Record<string, Feature> | null>

getSegmentGroup

Parameters

Returns Promise<SegmentGroup | null>

ProtectedsafeFetch

Type Parameters

Parameters

Returns Promise<T | null>

ProtectedsafeFetchAll

Type Parameters

Parameters

Returns Promise<Record<string, T> | null>

subscribeToAllFeatureConditons

Parameters

Returns Unsubscribe

subscribeToAllSegmentGroups

Parameters

Returns Unsubscribe

subscribeToFeatureConditon

Parameters

Returns Unsubscribe

subscribeToFeatureFlag

Parameters

Returns Unsubscribe

subscribeToFeatureFlags

Parameters

Returns Unsubscribe

subscribeToSegmentGroup

Parameters

Returns Unsubscribe

Settings

On This Page

`Protected` `Readonly`db

`Protected`prefetchPromise

`Static`Feature

`Protected`safeFetch

`Protected`safeFetchAll