// getting tag from 19.1.3.6 Object.prototype.toString() var cof = require('./$.cof') , TAG = require('./$.wks')('toStringTag') // ES3 wrong here , ARG = cof(function(){ return arguments; }()) == 'Arguments'; module.exports = function(it){ var O, T, B; return it === undefined ? 'Undefined' : it === null ? 'Null' // @@toStringTag case : typeof (T = (O = Object(it))[TAG]) == 'string' ? T // builtinTag case : ARG ? cof(O) // ES3 arguments fallback : (B = cof(O)) == 'Object' && typeof O.callee == 'function' ? 'Arguments' : B; };