/** @hidden */
export declare type FeatureFlagOptions = {
    percent?: number;
    filter?: () => Promise<boolean>;
};
/** Load feature flags, storing any new ones from the URL payload. */
export declare function initFeatureFlags(): Promise<void>;
/** @hidden */
export declare function createFeatureFlag(name: string, opts?: FeatureFlagOptions): Promise<void>;
/** @hidden */
export declare function setFeatureFlagEnabled(name: string, enabled: boolean): void;
/** @hidden Returns true if the user has the given feature flag. */
export declare function featureFlagIsEnabled(name: string): boolean;