/**
 * Increase string a value with unit
 *
 * @example '2px' + 1 = '3px'
 * @example '15em' + (-2) = '13em'
 */
export declare function increaseWithUnit(target: number, delta: number): number;
export declare function increaseWithUnit(target: string, delta: number): string;
export declare function increaseWithUnit(target: string | number, delta: number): string | number;