1const util = require('util'); 2const assert = require('assert'); 3 4class deprecatedClass { 5} 6 7const deprecated = util.deprecate(deprecatedClass, 'deprecatedClass is deprecated.'); 8 9const instance = new deprecated(); 10const deprecatedInstance = new deprecatedClass(); 11 12assert(instance instanceof deprecated); 13assert(instance instanceof deprecatedClass); 14assert(deprecatedInstance instanceof deprecated); 15assert(deprecatedInstance instanceof deprecatedClass); 16