import type { TransportRecord, TransportOptions, IBufferedTransport, HookLogEntry } from '../types/index.js';
/**
 * Options for {@link FileTransport}. Uses `destination` as the file path in
 * Node and as a `localStorage` key in the browser (the path component is
 * sanitised to `[a-zA-Z0-9_-]`).
 *
 */
export interface FileTransportOptions extends TransportOptions {
    /**
     * Where to write. In Node this is a file path (resolved relative to
     * `process.cwd()` and sanitised against path traversal). In the browser
     * this is a localStorage key (sanitised to alphanumeric + `-_`).
     * @default 'app.log' (Node) | 'better-logger:default' (browser)
     */
    destination?: string;
    /**
     * Optional hook fired when the transport cannot write (FS error,
     * quota exceeded, browser tab in private mode, ...). Receives a
     * synthetic {@link HookLogEntry}.
     */
    onError?: (entry: HookLogEntry) => void | Promise<void>;
}
/**
 * File-based transport.
 *
 * - In Node, writes batches via `fs.promises.appendFile` (non-blocking).
 * - In the browser, writes batches into `localStorage` (fallback no-op if
 *   `localStorage` is unavailable — e.g. private mode, sandboxed iframes).
 *
 * Fixed in 5.1.0:
 *   - BUG-N3: uses async `fs.promises.appendFile` instead of sync `appendFileSync`.
 *   - BUG-N4: destination is sanitised to reject path traversal (`..`, `~`, abs paths).
 *   - BUG-N5: dynamic `import('node:fs/promises')` instead of CJS `require('fs')`.
 *   - BUG-N6: browser case uses `localStorage` with try/catch (was silent no-op).
 *
 */
export declare class FileTransport implements IBufferedTransport {
    readonly name = "file";
    private buffer;
    private flushTimer?;
    private options;
    private closed;
    constructor(options?: FileTransportOptions);
    get bufferSize(): number;
    get maxBufferSize(): number;
    isReady(): boolean;
    write(record: TransportRecord): void;
    flush(): Promise<void>;
    private flushNode;
    private flushBrowser;
    close(): Promise<void>;
    private resolveNodeDestination;
    private resolveBrowserKey;
    private emitError;
}
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