/**
 * Formats a dollar amount. Supports negative values.
 */
export declare function formatDollars(amount: number | null | undefined): string;
/**
 * Formats a number as a percent. An input value of `1` means 100%.
 *
 * Supports negative values.
 *
 * @param purpose `'display'` if this percentage will be displayed, `'userInput'` if
 * percent will be used as the default value for a text input.
 * @param precision
 */
export declare function formatPercent(amount: number | null | undefined, purpose: 'display' | 'userInput', precision?: number): string;