3
var toStringTagSymbol = require('es6-symbol').toStringTag
5
, toString = Object.prototype.toString
7
, Global = (typeof Map === 'undefined') ? null : Map;
9
module.exports = function (x) {
10
return (x && ((Global && (x instanceof Global)) ||
11
(toString.call(x) === id) || (x[toStringTagSymbol] === 'Map'))) || false;