/**
 * Checks if a given string is exactly a non-negative integer.
 *
 * For example, it will accept strings such as:
 * - "0"
 * - "1"
 * - "94818981"
 *
 * And it will not accept strings such as:
 * - "0.0"
 * - "1.0"
 * - "-1"
 * - "foo"
 * - "0foo"
 * - "1.1"
 *
 * @param {string} input
 */
export declare const stringIsNonNegativeInteger: (input: string) => input is `${number}`;