import type { Event } from "../event.js";
import { Level } from "../level.js";
import type { SpanAttributes } from "../span.js";
import { ManagedSubscriber } from "./ManagedSubscriber.js";
/**
 * Options for the JsonSubscriber.
 */
export type JsonSubscriberOptions = {
    /**
     * The minimum level of logs to display.
     *
     * @default Level.INFO
     */
    level?: Level;
    /**
     * Include a timestamp in the message.
     *
     * @default true
     */
    timestamp?: boolean;
};
/**
 * The JsonSubscriber class is a subscriber which logs events to the console in JSON format.
 *
 * @example
 * ```ts
 * import { JsonSubscriber } from "@bcheidemann/tracing";
 *
 * // Initialize the subscriber and set it as the default global subscriber
 * // This should be called at the beginning of your program
 * JsonSubscriber.setGlobalDefault();
 * ```
 */
export declare class JsonSubscriber extends ManagedSubscriber {
    private readonly options;
    constructor(options?: JsonSubscriberOptions);
    /**
     * Initialises the JsonSubscriber as the default global subscriber.
     *
     * @deprecated Use `JsonSubscriber.setGlobalDefault()` instead
     */
    static init(options?: JsonSubscriberOptions): JsonSubscriber;
    static setGlobalDefault(options?: JsonSubscriberOptions): JsonSubscriber;
    protected onEvent(event: Event, spans: SpanAttributes[]): void;
    private displayMessage;
    private displaySpan;
    private formatFields;
    private displayLevel;
    private get timestamp();
}
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