export type DateTimeField = [string, number];
export type DateTimeNode = DateTimeField | string;
export declare const DATE_PATTERN_CHARS: any;
/**
 * Parse a datetime pattern into an array of nodes.
 */
export declare const parseDatePattern: (raw: string) => DateTimeNode[];
/**
 * Scan the date interval pattern and return the index of the first repeated field.
 */
export declare const intervalPatternBoundary: (pattern: DateTimeNode[]) => number;