import { BasePlacement, Placement } from './interface';
export declare const top = "top";
export declare const bottom = "bottom";
export declare const right = "right";
export declare const left = "left";
export declare const start = "start";
export declare const end = "end";
export declare const clippingParents = "clippingParents";
export declare const popper = "popper";
export declare const reference = "reference";
export declare const viewport = "viewport";
export declare const basePlacements: Array<BasePlacement>;
export declare const placements: Placement[];
export declare const INVALID_ELEMENT_ERROR = "Popper: Invalid reference or popper argument provided. They must be either a DOM element or virtual element.";