import { DatePipe } from '@angular/common';
import { DateHelperConfig } from './config';
export declare enum DateManipulateType {
    ADD = 0,
    SUBTRACT = 1,
}
export declare class DateHelper {
    private datePipe;
    private config;
    static units: string[];
    static unitMethodMap: {
        seconds: string;
        minutes: string;
        hours: string;
        date: string;
        month: string;
        year: string;
    };
    static unitAsMilliseconds: {
        seconds: 1000;
        minutes: 60000;
        hours: 3600000;
        date: 86400000;
    };
    constructor(datePipe: DatePipe, config: DateHelperConfig);
    isValidDateStr(dateStr: string): boolean;
    copy(source: Date | string | null): Date | null;
    getFirstDateOfMonth(year: number, month: number): Date;
    getLastDateOfMonth(year: number, month: number): Date;
    format(date: Date, pattern: string): string | null;
    manipulate(date: Date, type: DateManipulateType, amount: number, unit: string): void;
    add(date: Date, amount: number, unit: string): void;
    subtract(date: Date, amount: number, unit: string): void;
    unify(date: Date, unit: string): void;
    diff(source: Date, target: Date, unit: string): number;
}