import { BoxStyle, ContentPlaceholderRows, ContentPlaceholderStyledRows } from '../types';
/**
 * Tell whether a value is a unitless flex-basis number (e.g. `2` or `'2'`).
 *
 * @param value - The candidate box size.
 * @returns `true` when the value is purely numeric.
 * @example
 * isFlexBasis(2) // true
 * isFlexBasis('20px') // false
 */
declare function isFlexBasis(value: string | number): boolean;
/**
 * Tell whether a value is a CSS width with a supported unit (px, %, em, rem).
 *
 * @param value - The candidate box size.
 * @returns `true` when the value is a number followed by a supported unit.
 * @example
 * isWidth('20px') // true
 * isWidth(20) // false
 */
declare function isWidth(value: string | number): boolean;
/**
 * Build the flexbox style declarations for a single placeholder box.
 *
 * @param left - The leading spacer size; `0` means no spacer.
 * @param width - The box size, either a flex-grow factor or a CSS width.
 * @param isLast - Whether this box is the last in its row.
 * @param subClass - The CSS sub-class applied to spacer boxes.
 * @returns The ordered list of box styles for the spacer, the box, and the trailing filler.
 */
declare function getBoxStyle(left: number, width: number, isLast: boolean, subClass?: string): BoxStyle[];
/**
 * Turn placeholder rows of raw box sizes into rows of computed flexbox styles.
 *
 * @param rows - The placeholder rows, each box expressed as `[left, width]`.
 * @param subClass - The CSS sub-class applied to spacer boxes.
 * @returns The rows with their boxes converted to style declarations.
 */
declare function formatRows(rows: ContentPlaceholderRows, subClass?: string): ContentPlaceholderStyledRows;
export { isFlexBasis, isWidth, getBoxStyle, formatRows };