index.d.ts

/**
 * This is the API reference for the LaunchDarkly Client-Side SDK for React Native.
 *
 * In typical usage, you will instantiate [[LDClient]] and then call [[configure]] once at startup time to 
 * set up your connection to LaunchDarkly.
 *
 * For more information, see the [SDK reference guide](https://docs.launchdarkly.com/sdk/client-side/react-native).
 */
declare module 'launchdarkly-react-native-client-sdk' {

    /**
     * Configuration options for the LaunchDarkly React Native SDK.
     */
    export type LDConfig = {
        /**
         * The mobile SDK key associated with your LaunchDarkly environment.
         * 
         * This field is required as the React Native SDK will use this value to uniquely 
         * identify your LaunchDarkly account.
         */
        mobileKey: string;

        /**
         * The base URI for the LaunchDarkly polling server.
         *
         * Most users should use the default value.
         */
        pollUri?: string;

        /**
         * The base URI for the LaunchDarkly streaming server.
         *
         * Most users should use the default value.
         */
        streamUri?: string;

        /**
         * The base URI for the LaunchDarkly events server.
         *
         * Most users should use the default value.
         */
        eventsUri?: string;

        /**
         * The capacity of the analytics events queue.
         * 
         * The client buffers up to this many events in memory before flushing. If the capacity is exceeded
         * before the queue is flushed, events will be discarded. Increasing the capacity means that events
         * are less likely to be discarded, at the cost of consuming more memory. Note that in regular usage
         * flag evaluations do not produce individual events, only summary counts, so you only need a large
         * capacity if you are generating a large number of click, pageview, or identify events (or if you
         * are using the event debugger).
         * 
         * The default value is 100.
         */
        eventsCapacity?: number;

        /**
         * The interval in between flushes of the analytics events queue, in milliseconds.
         *
         * The default value is 30000ms (30 seconds).
         */
        eventsFlushIntervalMillis?: number;
        
        /**
         * The timeout interval for connecting to LaunchDarkly for flag requests and event reports.
         * 
         * The default value is 10000ms (10 seconds).
         */
        connectionTimeoutMillis?: number;

        /**
         * The interval by which the SDK polls for flag updates when the application is in the foreground. This
         * property is only used if is the streaming connection is disabled.
         * 
         * The default value is 300000ms (5 min).
         */
        pollingIntervalMillis?: number;

        /**
         * The interval by which the SDK polls for flag updates when the application is in the background.
         * 
         * The default value is 3600000ms (1 hour).
         */
        backgroundPollingIntervalMillis?: number;

        /**
         * Whether or not to use the REPORT verb to fetch flag settings.
         *
         * If this is true, flag settings will be fetched with a REPORT request
         * including a JSON entity body with the user object.
         *
         * Otherwise (by default) a GET request will be issued with the user passed as
         * a base64 URL-encoded path parameter.
         *
         * Do not use unless advised by LaunchDarkly.
         */
        useReport?: boolean;

        /**
         * Whether or not to open a streaming connection to LaunchDarkly for live flag updates.
         *
         * If this is true, the client will always attempt to maintain a streaming connection; if false,
         * it never will. 
         * 
         * The default value is true.
         */
        stream?: boolean;

        /**
         * Whether or not the SDK should attempt to check for flag updates while the application
         * runs in the background.
         * 
         * If this is true, the client will periodically poll for updates while in the background; if
         * false, the SDK will not attempt to receive updates while the app is backgrounded.
         * 
         * The default value is false.
         */
        disableBackgroundUpdating?: boolean;

        /**
         * Disables all network calls from the LaunchDarkly SDK.
         * 
         * This can also be specified after the client has been created, using LDClient.setOffline().
         * 
         * The default value is true (the client will make network calls).
         */
        offline?: boolean;

        /**
         * Controls information logged to the console, and modifying some setting ranges to facilitate debugging.
         * 
         * This setting is only used when running in iOS. In Android this setting is ignored.
         * 
         * The default value is false.
         */
        debugMode?: boolean;

        /**
         * Whether LaunchDarkly should provide additional information about how flag values were
         * calculated.
         *
         * The additional information will then be available through the client's
         * `LDClient.*VariationDetail` methods. Since this increases the size of network requests,
         * such information is not sent unless you set this option to true.
         */
        evaluationReasons?: boolean;

        /**
         * Setting for the maximum number of locally cached users. Default is 5 users.
         */
        maxCachedUsers?: number;

        /**
         * Setting for whether sending diagnostic data about the SDK is disabled. The default is false.
         */
        diagnosticOptOut?: boolean;

        /**
         * The time interval between sending periodic diagnostic data. The default is 900000 (15 minutes).
         */
        diagnosticRecordingIntervalMillis?: number;

        /**
         * The mapping of environment names as keys to mobile keys for each environment as values.
         */
        secondaryMobileKeys?: Record<string, string>;

        /**
         * Whether to treat all user attributes as private for event reporting for all users.
         * The SDK will not include private attribute values in analytics events, but private attribute names will be sent. 
         * The default is false.
         */
        allUserAttributesPrivate?: boolean;
    };
  
    /**
     * A LaunchDarkly user object.
     */
    export type LDUser = {

        /**
         * A unique string identifying a user.
         */
        key: string;

        /**
         * The secondary key for the user. See the 
         * [documentation](https://docs.launchdarkly.com/home/managing-flags/targeting-users#percentage-rollout-logic) 
         * for more information on it's use for percentage rollout bucketing.
         */
        secondary?: string;

        /**
         * The user's name.
         *
         * You can search for users on the User page by name.
         */
        name?: string;

        /**
         * The user's first name.
         */
        firstName?: string;

        /**
         * The user's last name.
         */
        lastName?: string;

        /**
         * The user's email address.
         */
        email?: string;

        /**
         * Whether to show the user on the Users page in LaunchDarkly.
         * 
         * The default value is false.
         */
        anonymous?: boolean;

        /**
         * The country associated with the user.
         */
        country?: string;

        /**
         * Specifies a list of attribute names (either built-in or custom) which should be
         * marked as private, and not sent to LaunchDarkly in analytics events.
         */
        privateAttributeNames?: string[];

        /**
         * Any additional attributes associated with the user.
         */
        custom?: { [key: string]: any };

        /**
         * The IP address associated with the user.
         */
        ip?: string;

        /**
         * The avatar associated with the user.
         */
        avatar?: string;
    };
  
    /**
     * Describes the kind of error which occurred when a flag evaluation was calculated.
     * 
     * This extends String for backwards compatibility. In a future major release, references to this type
     * may be replaced with String references.
     */
    export interface LDEvaluationReasonErrorKind extends String {
    }
  
    /**
     * Describes the reason behind how a flag evaluation was calculated.
     * 
     * This extends String for backwards compatibility. In a future major release, references to this type
     * may be replaced with String references.
     */
    export interface LDEvaluationReasonKind extends String {
    }

    /**
     * Describes what state of connection to LaunchDarkly the SDK is in.
     * 
     * This extends String for backwards compatibility. In a future major release, references to this type
     * may be replaced with String references.
     */
    export interface LDConnectionMode extends String {
    }

    /**
     * Describes why a connection request to LaunchDarkly failed.
     * 
     * This extends String for backwards compatibility. In a future major release, references to this type
     * may be replaced with String references.
     */
    export interface LDFailureReason extends String {
    }
  
    /**
     * The flag is off and therefore returned its configured off value.
     */
    export type LDEvaluationReasonOff = {
        kind: 'OFF';
    };
  
    /**
     * The flag is on, but the user did not match any targets or rules, so it returned the value that appears 
     * on the dashboard under "Default rule."
     */
    export type LDEvaluationReasonFallthrough = {
        kind: 'FALLTHROUGH';
    };
  
    /**
     * The user key was specifically targeted for this flag in the "Target individual users" section.
     */
    export type LDEvaluationReasonTargetMatch = {
        kind: 'TARGET_MATCH';
    };
  
    /**
     * The user who encountered the flag matched one of the flag's rules.
     */
    export type LDEvaluationReasonRuleMatch = {
        kind: 'RULE_MATCH';

        /**
         * The positional index of the matched rule (0 for the first rule).
         */
        ruleIndex: number;

        /**
         * The rule's unique identifier, which stays the same even if you rearrange the order of the rules.
         */
        ruleId: string;
    };
  
    /**
     * The flag had at least one prerequisite flag that either was off or did not return the desired variation. 
     * Because of this, the flag returned its "off" value.
     */
    export type LDEvaluationReasonPrerequisiteFailed = {
        kind: 'PREREQUISITE_FAILED';

        /**
         * The key of the prerequisite flag that failed.
         */
        prerequisiteKey: string;
    };
  
    /**
     * The flag could not be evaluated, so the default value was returned.
     */
    export type LDEvaluationReasonError = {
        kind: 'ERROR';

        /**
         * The kind of error which occurred.
         * 
         * Kinds of errors include:
         *
         * - `'CLIENT_NOT_READY'`: The client is not able to establish a connection to LaunchDarkly yet. If there is a persistent feature store, the store does not yet contain flag data.
         * - `'FLAG_NOT_FOUND'`: The flag key did not match any known flag.
         * - `'USER_NOT_SPECIFIED'`: The user object or user key was not provided.
         * - `'MALFORMED_FLAG'`: There was an internal inconsistency in the flag data. For example, a rule specified a nonexistent variation. This is an unusual condition that might require assistance from LaunchDarkly's Support team.
         * - `'WRONG_TYPE'`: The application code requested the flag value with a different data type than it actually is. For example, the code asked for a boolean when the flag type is actually a string.
         * - `'EXCEPTION'`: An unexpected error stopped flag evaluation. This could happen if you are using a persistent feature store and the database stops working. When this happens, the SDK always prints the specific error to the log.
         */
        errorKind: LDEvaluationReasonErrorKind;
    };
  
    /**
     * Describes the reason that a flag evaluation produced a particular value. This is
     * part of the [[LDEvaluationDetail]] object returned by the variation detail methods.
     */
    export type LDEvaluationReason =
        | LDEvaluationReasonOff
        | LDEvaluationReasonFallthrough
        | LDEvaluationReasonTargetMatch
        | LDEvaluationReasonRuleMatch
        | LDEvaluationReasonPrerequisiteFailed
        | LDEvaluationReasonError;
  
    /**
     * An object that combines the result of a feature flag evaluation with information about
     * how it was calculated.
     *
     * This is the result of calling one of the `LDClient.*VariationDetail` methods.
     *
     * For more information, see the [documentation](https://docs.launchdarkly.com/sdk/concepts/evaluation-reasons).
     * 
     * @typeparam T
     *   The type of flag being evaluated.
     */
    export type LDEvaluationDetail<T> = {
        /**
         * The result of the flag evaluation. This will be either one of the flag's variations or
         * the default value that was passed to the variation detail function.
         */
        value: T;

        /**
         * The index of the returned value within the flag's list of variations, e.g. 0 for the
         * first variation-- or `null` if the default value was returned.
         */
        variationIndex?: number;

        /**
         * An object describing the main factor that influenced the flag evaluation value.
         */
        reason: LDEvaluationReason;
    };

    /**
     * A map of feature flags from their keys to their values.
     */
    export interface LDFlagSet {
        [key: string]: any;
    }
    
    /**
     * The LaunchDarkly SDK client object.
     *
     * Applications should configure the client at application startup time and reuse the same instance.
     *
     * For more information, see the [SDK Reference Guide](https://docs.launchdarkly.com/sdk/client-side/react-native).
     */
    export default class LDClient {
        constructor();

        /**
         * Returns the SDK version.
         * 
         * @returns
         *   A string containing the SDK version.
         */
        getVersion(): string;

        /**
         * Initialize the SDK to work with the specified client configuration options and on behalf of the specified user.
         * Will block for a number of seconds represented until flags are received from LaunchDarkly if the timeout parameter
         * is passed.
         * 
         * This should only be called once at application start time.
         * 
         * @param config 
         *   the client configuration options
         * @param user 
         *   the user
         * @param timeout
         *   (Optional) A number representing how long to wait for flags
         */
        configure(config: LDConfig, user: LDUser, timeout?: number): Promise<null>;
        
        /**
         * Determines the variation of a boolean feature flag for the current user.
         *
         * @param flagKey
         *   The unique key of the feature flag.
         * @param defaultValue
         *   The default value of the flag, to be used if the value is not available from LaunchDarkly.
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns
         *   A promise containing the flag's value.
         */
        boolVariation(flagKey: string, defaultValue: boolean, environment?: string): Promise<boolean>;

        /**
         * Determines the variation of an integer feature flag for the current user.
         *
         * @param flagKey
         *   The unique key of the feature flag.
         * @param defaultValue
         *   The default value of the flag, to be used if the value is not available from LaunchDarkly.
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns
         *   A promise containing the flag's value.
         */
        intVariation(flagKey: string, defaultValue: number, environment?: string): Promise<number>;

        /**
         * Determines the variation of a floating-point feature flag for the current user.
         *
         * @param flagKey
         *   The unique key of the feature flag.
         * @param defaultValue
         *   The default value of the flag, to be used if the value is not available from LaunchDarkly.
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns
         *   A promise containing the flag's value.
         */
        floatVariation(flagKey: string, defaultValue: number, environment?: string): Promise<number>;

        /**
         * Determines the variation of a string feature flag for the current user.
         *
         * @param flagKey
         *   The unique key of the feature flag.
         * @param defaultValue
         *   The default value of the flag, to be used if the value is not available from LaunchDarkly.
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns
         *   A promise containing the flag's value.
         */
        stringVariation(flagKey: string, defaultValue: string, environment?: string): Promise<string>;

        /**
         * Determines the variation of a JSON feature flag for the current user.
         *
         * @param flagKey
         *   The unique key of the feature flag.
         * @param defaultValue
         *   The default value of the flag, to be used if the value is not available from LaunchDarkly.
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns
         *   A promise containing the flag's value.
         */
        jsonVariation(
            flagKey: string,
            defaultValue: Record<string, any>,
            environment?: string
        ): Promise<Record<string, any>>;
        
        /**
         * Determines the variation of a boolean feature flag for a user, along with information about how it was
         * calculated.
         *
         * Note that this will only work if you have set `evaluationReasons` to true in [[LDConfig]].
         * Otherwise, the `reason` property of the result will be null.
         *
         * For more information, see the [SDK reference guide](https://docs.launchdarkly.com/sdk/concepts/evaluation-reasons).
         *
         * @param flagKey
         *   The unique key of the feature flag.
         * @param defaultValue
         *   The default value of the flag, to be used if the value is not available from LaunchDarkly.
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns
         *   A promise containing an [[LDEvaluationDetail]] object containing the value and explanation.
         */
        boolVariationDetail(
            flagKey: string,
            defaultValue: boolean,
            environment?: string
        ): Promise<LDEvaluationDetail<boolean>>;

        /**
         * Determines the variation of an integer feature flag for a user, along with information about how it was
         * calculated.
         *
         * Note that this will only work if you have set `evaluationReasons` to true in [[LDConfig]].
         * Otherwise, the `reason` property of the result will be null.
         *
         * For more information, see the [SDK reference guide](https://docs.launchdarkly.com/sdk/concepts/evaluation-reasons).
         *
         * @param flagKey
         *   The unique key of the feature flag.
         * @param defaultValue
         *   The default value of the flag, to be used if the value is not available from LaunchDarkly.
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns
         *   A promise containing an [[LDEvaluationDetail]] object containing the value and explanation.
         */
        intVariationDetail(
            flagKey: string,
            defaultValue: number,
            environment?: string
        ): Promise<LDEvaluationDetail<number>>;

        /**
         * Determines the variation of a floating-point feature flag for a user, along with information about how it was
         * calculated.
         *
         * Note that this will only work if you have set `evaluationReasons` to true in [[LDConfig]].
         * Otherwise, the `reason` property of the result will be null.
         *
         * For more information, see the [SDK reference guide](https://docs.launchdarkly.com/sdk/concepts/evaluation-reasons).
         *
         * @param flagKey
         *   The unique key of the feature flag.
         * @param defaultValue
         *   The default value of the flag, to be used if the value is not available from LaunchDarkly.
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns
         *   A promise containing an [[LDEvaluationDetail]] object containing the value and explanation.
         */
        floatVariationDetail(
            flagKey: string,
            defaultValue: number,
            environment?: string
        ): Promise<LDEvaluationDetail<number>>;

        /**
         * Determines the variation of a string feature flag for a user, along with information about how it was
         * calculated.
         *
         * Note that this will only work if you have set `evaluationReasons` to true in [[LDConfig]].
         * Otherwise, the `reason` property of the result will be null.
         *
         * For more information, see the [SDK reference guide](https://docs.launchdarkly.com/sdk/concepts/evaluation-reasons).
         *
         * @param flagKey
         *   The unique key of the feature flag.
         * @param defaultValue
         *   The default value of the flag, to be used if the value is not available from LaunchDarkly.
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns
         *   A promise containing an [[LDEvaluationDetail]] object containing the value and explanation.
         */
        stringVariationDetail(
            flagKey: string,
            defaultValue: string,
            environment?: string
        ): Promise<LDEvaluationDetail<string>>;

        /**
         * Determines the variation of a JSON feature flag for a user, along with information about how it was
         * calculated.
         *
         * Note that this will only work if you have set `evaluationReasons` to true in [[LDConfig]].
         * Otherwise, the `reason` property of the result will be null.
         *
         * For more information, see the [SDK reference guide](https://docs.launchdarkly.com/sdk/concepts/evaluation-reasons).
         *
         * @param flagKey
         *   The unique key of the feature flag.
         * @param defaultValue
         *   The default value of the flag, to be used if the value is not available from LaunchDarkly.
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns
         *   A promise containing an [[LDEvaluationDetail]] object containing the value and explanation.
         */
        jsonVariationDetail(
            flagKey: string,
            defaultValue: Record<string, any>,
            environment?: string
        ): Promise<LDEvaluationDetail<Record<string, any>>>;
        
        /**
         * Returns a map of all available flags to the current user's values.
         *
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns
         *   A promise containing an object in which each key is a feature flag key and each value is the flag value.
         *   The promise will be rejected if the SDK has not yet completed initialization.
         *   Note that there is no way to specify a default value for each flag as there is with the
         *   `*Variation` methods, so any flag that cannot be evaluated will have a null value.
         */
        allFlags(environment?: string): Promise<LDFlagSet>;
        
        /**
         * Track events to use in goals or A/B tests.
         *
         * @param eventName
         *   The name of the event, which may correspond to a goal in A/B tests.
         * @param data
         *   Optional additional information to associate with the event.
         * @param metricValue
         *   Optional numeric value to attach to the tracked event
         * @param environment
         *   Optional string to execute the function in a different environment than the default.
         */
        track(eventName: string, data?: any, metricValue?: number, environment?: string): void;
        
        /**
         * Checks whether the client has been put into offline mode. This is true only if [[setOffline]]
         * was called, or if the configuration had [[LDConfig.offline]] set to true,
         * not if the client is simply offline due to a loss of network connectivity.
         *
         * @returns 
         *   A promise containing true if the client is in offline mode
         */
        isOffline(): Promise<boolean>;

        /**
         * Shuts down any network connections maintained by the client and puts the client in offline
         * mode, preventing the client from opening new network connections until [[setOnline]] is called.
         * 
         * Note: The client automatically monitors the device's network connectivity and app foreground
         * status, so calling [[setOffline]] or [[setOnline]] is normally unnecessary in most situations.
         * 
         * @returns 
         *   A promise containing true if the change was made successfully
         */
        setOffline(): Promise<boolean>;

        /**
         * Restores network connectivity for the client, if the client was previously in offline mode.
         * This operation may be throttled if it is called too frequently.
         * 
         * Note: The client automatically monitors the device's network connectivity and app foreground
         * status, so calling [[setOffline]] or [[setOnline]] is normally unnecessary in most situations.
         * 
         * @returns 
         *   A promise containing true if the change was made successfully
         */
        setOnline(): Promise<boolean>;

        /**
         * Checks whether the client is ready to return feature flag values. This is true if either
         * the client has successfully connected to LaunchDarkly and received feature flags, or the
         * client has been put into offline mode (in which case it will return only default flag values).
         * 
         * This function only works when running in Android. On iOS, this function will return a rejected promise.
         *
         * @param environment
         *   Optional environment name to obtain the result from the corresponding secondary environment
         * @returns 
         *   A promise contianing true if the client is initialized or offline
         */
        isInitialized(environment?: string): Promise<boolean>;
        
        /**
         * Flushes all pending analytics events.
         *
         * Normally, batches of events are delivered in the background at intervals determined by the
         * `eventsFlushIntervalMillis` property of [[LDConfig]]. Calling `flush` triggers an 
         * immediate delivery.
         */
        flush(): void;
        
        /**
         * Shuts down the client and releases its resources, after delivering any pending analytics
         * events. After the client is closed, all calls to the `*Variation` methods will return default values,
         * and it will not make any requests to LaunchDarkly.
         */
        close(): Promise<void>;
        
        /**
         * Sets the current user, retrieves flags for that user, then sends an Identify Event to LaunchDarkly.
         *
         * @param user
         *   The user for evaluation and event reporting
         * @returns 
         *   A promise indicating when this operation is complete (meaning that flags are ready for evaluation).
         */
        identify(user: LDUser): Promise<null>;
        
        /**
         * Registers a callback to be called when the flag with key `flagKey` changes from its current value. 
         *
         * @param flagKey
         *   The flag key to attach the callback to
         * @param callback 
         *   The callback to attach to the flag key
         * @param environment
         *   Optional string to execute the function in a different environment than the default.
         */
        registerFeatureFlagListener(
            flagKey: string,
            callback: (flagKey: string) => void,
            environment?: string
        ): void;

        /**
         * Unregisters a callback for the flag with key `flagKey`.
         *
         * @param flagKey  
         *   The flag key to remove the callback from
         * @param callback 
         *   The callback to remove from the flag key
         * @param environment
         *   Optional string to execute the function in a different environment than the default.
         */
        unregisterFeatureFlagListener(
            flagKey: string,
            callback: (flagKey: string) => void,
            environment?: string
        ): void;

        /**
         * Returns the current state of the connection to LaunchDarkly.
         * 
         * States include:
         *
         * - `'STREAMING'`: The SDK is either connected to the flag stream, or is actively attempting to acquire a connection.
         * - `'POLLING'`: The SDK was configured with streaming disabled, and is in foreground polling mode.
         * - `'BACKGROUND_POLLING'`: (Android specific enum value) The SDK has detected the application is in the background and has transitioned to battery conscious background polling.
         * - `'BACKGROUND_DISABLED'`: (Android specific enum value) The SDK was configured with background polling disabled. The SDK has detected the application is in the background and is not attempting to update the flag cache.
         * - `'OFFLINE'`: The SDK has detected that the mobile device does not have an active network connection so has ceased flag update attempts until the network status changes.
         * - `'SET_OFFLINE'`: (Android specific enum value) The SDK has been explicitly set offline, either in the initial configuration, by setOffline(), or as a result of failed authentication to LaunchDarkly. The SDK will stay offline unless setOnline() is called.
         * - `'SHUTDOWN'`: (Android specific enum value) The shutdown state indicates the SDK has been permanently shutdown as a result of a call to close().
         * - `'ESTABLISHING_STREAMING_CONNECTION'`: (iOS specific enum value) The SDK is attempting to connect to LaunchDarkly by streaming.
         * 
         * @param environment
         *   Optional string to execute the function in a different environment than the default.
         * @returns 
         *   A promise containing a LDConnectionMode enum value representing the status of the connection to LaunchDarkly.
         */
        getConnectionMode(environment?: string): Promise<LDConnectionMode>;

        /**
         * Returns the most recent successful flag cache update in millis from the epoch
         * or null if flags have never been retrieved.
         *
         * @param environment
         *   Optional string to execute the function in a different environment than the default.
         * @returns 
         *   A promise containing a number representing the status of the connection to LaunchDarkly, 
         *   or null if a successful connection has yet to be established.
         */
        getLastSuccessfulConnection(environment?: string): Promise<number | null>;

        /**
         * Most recent unsuccessful flag cache update attempt in millis from the epoch
         * or null if flag update has never been attempted.
         *
         * @param environment
         *   Optional string to execute the function in a different environment than the default.
         * @returns 
         *   A promise containing a number representing the status of the connection to LaunchDarkly, 
         *   or null if a failed connection has yet to occur.
         */
        getLastFailedConnection(environment?: string): Promise<number | null>;

        /**
         * Returns the most recent connection failure reason or null.
         * 
         * Reasons include:
         *
         * - `'NONE'`: This indicates when no error has been recorded.
         * - `'UNKNOWN_ERROR'`: This indicates when there is an internal error in the stream request.
         * - `'UNAUTHORIZED'`: (iOS specific enum value) This indicates when an incorrect mobile key is provided.
         * - `'HTTP_ERROR'`: (iOS specific enum value) This indicates when an error with an HTTP error code is present.
         * - `'UNEXPECTED_RESPONSE_CODE'`: (Android specific enum value) This indicates the LDFailure is an instance of LDInvalidResponseCodeFailure. See Android documentation for more details.
         * - `'UNEXPECTED_STREAM_ELEMENT_TYPE'`: (Android specific enum value) An event was received through the stream was had an unknown event name. This could indicate a newer SDK is available if new event types have become available through the flag stream since the SDKs release.
         * - `'NETWORK_FAILURE'`: (Android specific enum value) A network request for polling, or the EventSource stream reported a failure.
         * - `'INVALID_RESPONSE_BODY'`: (Android specific enum value) A response body received either through polling or streaming was unable to be parsed.
         * 
         * @param environment
         *   Optional string to execute the function in a different environment than the default.
         * @returns 
         *   A promise containing a LDFailureReason enum value representing the reason for the most recently failed 
         *   connection to LaunchDarkly, or null if a failed connection has yet to occur.
         */
        getLastFailure(environment?: string): Promise<LDFailureReason | null>;
        
        /**
         * Registers a callback to be called on connection status updates.
         * 
         * @param listenerId 
         *   The listener to be called on a connection status update
         * @param callback
         *   The callback to attach to the connection status update
         * @param environment
         *   Optional string to execute the function in a different environment than the default.
         */
        registerCurrentConnectionModeListener(
            listenerId: string,
            callback: (connectionMode: string) => void,
            environment?: string
        ): void;

        /**
         * Unregisters a callback so that it will no longer be called on connection status updates.
         * 
         * @param listenerId 
         *   The listener to remove the callback from
         * @param environment
         *   Optional string to execute the function in a different environment than the default.
         */
        unregisterCurrentConnectionModeListener(listenerId: string, environment?: string): void;
        
        /**
         * Registers a callback to be called when a flag update is processed by the SDK.
         * 
         * @param listenerId 
         *   The listener to be called when a flag update is processed
         * @param callback
         *   The callback to attach to the flag update
         * @param environment
         *   Optional string to execute the function in a different environment than the default.
         */
        registerAllFlagsListener(
            listenerId: string,
            callback: (updatedFlags: string[]) => void,
            environment?: string
        ): void;

        /**
         * Unregisters a callback so it will no longer be called on flag updates.
         * 
         * @param listenerId 
         *   The listener to be removed
         * @param environment
         *   Optional string to execute the function in a different environment than the default.
         */
        unregisterAllFlagsListener(listenerId: string, environment?: string): void;
    }
  }