export declare class ValueHelper {
    static isNull(value: unknown): value is null | undefined;
    static isString(value: unknown): value is string;
    static isNumber(value: unknown): value is number;
    static isBoolean(value: unknown): value is boolean;
    static isDate(value: unknown): value is Date;
    static isObject(value: unknown): value is object;
    static hasValueProperty(value: unknown): value is {
        label: string;
        value: unknown;
    };
    static isCheckboxInput(element: Element): element is HTMLInputElement;
    static isDateInput(element: Element): element is HTMLInputElement;
    static isNumberInput(element: Element): element is HTMLInputElement;
    static isComboboxDiv(element: Element): element is HTMLDivElement;
    static isFormElement(element: Element): element is HTMLInputElement | HTMLSelectElement | HTMLTextAreaElement;
    static extractValueString(value: unknown): string;
}