export declare namespace Task {
    type Constraint = (date: Date) => boolean;
}
export declare abstract class Task {
    constraints: Task.Constraint[];
    /**
     * Run every minute.
     */
    everyMinute(): this;
    /**
     * Run hourly at the top.
     */
    hourly(): this;
    /**
     * Run daily at midnight UTC.
     */
    daily(): this;
    /**
     * Run daily at a specific time UTC.
     */
    dailyAt(time: string): this;
    /**
     * Run weekly on Sunday at midnight UTC.
     */
    weekly(): this;
    /**
     * Run weekly on a specific day of the week at a specific time UTC.
     */
    weeklyOn(day: string, time: string): this;
    /**
     * Run monthly on the first day of the month at midnight UTC.
     */
    monthly(): this;
    /**
     * Run monthly on a specific date of the month at a specific time UTC.
     */
    monthlyOn(date: string, time: string): this;
    yearly(): this;
    abstract perform(): Promise<void>;
}