class classification ecma ecmascript internal javascript native node node-js nodejs spec specification stdlib tostring type typeof util utilities utility utils

built-in check is istype javascript node node-js nodejs stdlib type typeof util utilities utility utils

check class constructor ctor instanceof is istype javascript name node node-js nodejs stdlib type typeof util utilities utility utils

class detect es2015 es6 feature has javascript node node-js nodejs stdlib support symbol tostringtag type typeof util utilities utility utils

assert assertion check is isobjectlike javascript node node-js nodejs obj object object-like stdlib type typeof util utilities utility utils validate

assert assertion class classification equal is issame javascript native node node-js nodejs same stdlib type typeof util utilities utility utils

assert assertion check equal is issametype javascript node node-js nodejs same stdlib strict type typeof util utilities utility utils valid