export declare type OrderBookOptions = {
    symbol: `${string}FP`;
    level: 20 | 50;
};
export declare type OrderBookResponse = {
    e: string;
    t: number;
    asks: [number, number][];
    bids: [number, number][];
};
export declare function fetchOrderBook({ symbol, level }: OrderBookOptions, init?: RequestInit): Promise<OrderBookResponse>;