/**
 * check Symbol support
 * @returns true/false
 */
export declare const hasSymbol: false | ((key: string) => symbol);
/**
 * warn if condition is not pass
 * @param condition condition
 * @param format format
 * @param args args
 */
export declare function warn(condition: boolean, format: string, ...args: any[]): void;
/**
 * throw error if condition is not pass
 * @param condition condition
 * @param err error message or error object
 */
export declare function assert(condition: boolean, err: string | Error): void;
/**
 * print a colorful message in console
 * @param title title
 * @param content content
 */
export declare function print(title: string, content: string): void;