export interface JsonStreamOptions {
    /**
     * Destination file path where the stream will be written.
     */
    filePath: string;
    /**
     * Template containing the placeholder.
     * Defaults to a plain JSON array.
     */
    template?: string;
    /**
     * Placeholder token used inside the template where JSON lines will be injected.
     */
    placeholder?: string;
}
export declare class JsonStream {
    private stream;
    private firstChunk;
    private readonly prefix;
    private readonly suffix;
    private readonly filePath;
    constructor(options: JsonStreamOptions);
    open(): void;
    write(entry: unknown): void;
    close(suffixData?: Record<string, unknown>): Promise<void>;
    private buildSuffix;
}