/**
 * Generate unique IDs for use as pseudo-private/protected names.
 * Similar in concept to
 * <http://wiki.ecmascript.org/doku.php?id=strawman:names>.
 *
 * The goals of this function are twofold:
 *
 * * Provide a way to generate a string guaranteed to be unique when compared
 *   to other strings generated by this function.
 * * Make the string complex enough that it is highly unlikely to be
 * accidentally duplicated by hand (this is key if you're using `ID`
 * as a private/protected name on an object).
 * @author gordonbrander https://gist.github.com/gordonbrander/2230317
 * @example
 *     var privateName = ID();
 *     var o = { 'public': 'foo' };
 *     o[privateName] = 'bar';
 **/
export declare const genId: (length?: number, prefix?: string) => string;