export declare const FIELD_VALUE_BRAND: unique symbol;
export type FieldValueMethod = 'serverTimestamp' | 'increment' | 'arrayUnion' | 'arrayRemove' | 'deleteField';
export declare class FieldValue {
    readonly [FIELD_VALUE_BRAND] = true;
    readonly _isFieldValue: boolean;
    readonly method: FieldValueMethod;
    readonly value?: any;
    constructor(method: FieldValueMethod, value?: any);
    static isFieldValue(val: any): val is FieldValue;
    toJSON(): {
        _isFieldValue: boolean;
        method: FieldValueMethod;
        value: any;
    };
    isEqual(other: any): boolean;
}
export declare const serverTimestamp: () => FieldValue;
export declare const increment: (n: number) => FieldValue;
export declare const arrayUnion: (...elements: any[]) => FieldValue;
export declare const arrayRemove: (...elements: any[]) => FieldValue;
export declare const deleteField: () => FieldValue;
export declare const atomicIncrement: (n: number) => FieldValue;
export declare const atomicDecrement: (n: number) => FieldValue;