/**
 * @file Word-case helpers — `capitalize()` produces an upper-first / lower-rest
 *   variant that iterates by code point so surrogate pairs aren't split.
 */
/**
 * Capitalize the first letter of a word.
 *
 * @example
 *   ;```typescript
 *   capitalize('hello') // 'Hello'
 *   capitalize('WORLD') // 'World'
 *   capitalize('') // ''
 *   ```
 */
export declare function capitalize(word: string): string;
