/**
 * Converts falsy values `null`, `undefined`, `0`, `false` and empty strings
 * to false. Otherwise the value is returned as true
 * @param value
 * @returns
 */
export declare function toBoolean(value: unknown): boolean;
/**
 * Transform a boolean value or leave undefined if not present
 * @param field - the property name of the value to transform in the object
 * @returns PropertyDecorator
 */
export declare function ToBoolean(field: string): PropertyDecorator;