/**
 * Check if a string is blank or not.
 *
 * A string is considered to be blank iff is a falsy value or is empty after
 * trimmed.
 *
 * @param string a string to be evaluated
 * @returns boolean true if string is blank, otherwises false.
 * @see isEmpty
 */
export declare function isBlank(str: string): boolean;
/**
 * Check if a string is empty or not.
 *
 * A string is considered to be empty iff have length equal to 0.
 *
 * @param string a string to be evaluated
 * @returns boolean true if string is empty, otherwises false.
 */
export declare function isEmpty(str: string): boolean;