export interface RingBufferEntry<T> {
    data: T;
    readonly timestamp: number;
    readonly index: number;
}
export type RingBufferSlice<T> = readonly RingBufferEntry<T>[];

export declare class RingBuffer<T> {
    private readonly entries;
    private readonly capacity;
    private nextIndex;
    private totalAppended;
    constructor(capacity: number);
    
    append(item: T): RingBufferEntry<T>;
    
    appendOrMerge(item: T, condition: (lastEntry: RingBufferEntry<T>) => boolean, merge: (last: T, next: T) => T): RingBufferEntry<T>;
    
    slice(): RingBufferSlice<T>;
    
    get size(): number;
    
    getLastN(n: number): RingBufferSlice<T>;
    
    getSinceIndex(index: number): {
        entries: RingBufferSlice<T>;
        nextIndex: number;
        oldestIndex: number;
    };
    
    clear(): void;
}