/**
 * Represents the result of processing an outbound topic name,
 * containing either the original topic name, a topic alias integer, or both.
 */
export interface OutboundTopicAlias {
    /**
     * The topic name.
     * Will be empty (`""`) when a valid alias mapping has already been established.
     */
    topicName: string;
    /**
     * The numeric alias assigned to the topic, if aliases are enabled.
     */
    topicAlias?: number;
}
/**
 * Manages outbound MQTT topic aliases using a Least Recently Used (LRU) caching strategy.
 */
export declare class OutboundTopicAliasManager {
    /**
     * The maximum number of topic aliases supported by the broker/client.
     */
    private readonly maxAliases;
    /**
     * Internal mapping from topic names to assigned aliases.
     * Leverages JavaScript's Map insertion-order behavior to act as an LRU cache.
     */
    private readonly topicToAlias;
    /**
     * Creates an instance of `OutboundTopicAliasManager`.
     *
     * @param clientTopicAliasMaximum - The maximum number of topic aliases allowed (defaults to `0`, meaning disabled).
     */
    constructor(clientTopicAliasMaximum?: number);
    /**
     * Processes an outbound topic name and returns the appropriate payload metadata
     * (`OutboundTopcAlias`) based on alias availability and caching state.
     *
     * - If aliases are disabled (`maxAliases === 0`), returns only the original `topicName`.
     * - If the topic is already cached (cache hit), refreshes its LRU position and returns the `topicAlias` with an empty `topicName`.
     * - If the topic is not cached (cache miss), assigns a new alias or evicts the least recently used topic alias mapping.
     *
     * @param topic - The outbound MQTT topic name to process.
     * @returns An object containing the formatted `topicName` and optional `topicAlias`.
     */
    processTopic(topic: string): OutboundTopicAlias;
    /**
     * Clears all internal topic alias mappings and releases cached resources.
     */
    destroy(): void;
}
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