import { ElementRef } from '@angular/core';
import { MDCComponent } from '@angular-mdc/web/base';
import { MDCSelectHelperTextFoundation } from '@material/select';
export declare class MDCSelectHelperText extends MDCComponent<MDCSelectHelperTextFoundation> {
    elementRef: ElementRef<HTMLElement>;
    id?: string;
    get persistent(): boolean;
    set persistent(value: boolean);
    private _persistent;
    get validation(): boolean;
    set validation(value: boolean);
    private _validation;
    constructor(elementRef: ElementRef<HTMLElement>);
    get foundation(): MDCSelectHelperTextFoundation;
    getDefaultFoundation(): MDCSelectHelperTextFoundation;
    /** Sets the validity of the helper text. */
    setValidity(inputIsValid: boolean): void;
    /** Makes the helper text visible to the screen reader. */
    showToScreenReader(): void;
    init(): void;
}