git.r.bdr.sh - rbdr/dotfiles/blob

   1 'use strict';
   2
   3 var toStringTagSymbol = require('es6-symbol').toStringTag
   4
   5   , toString = Object.prototype.toString
   6   , id = '[object WeakMap]'
   7   , Global = (typeof WeakMap === 'undefined') ? null : WeakMap;
   8
   9 module.exports = function (x) {
  10         return (x && ((Global && (x instanceof Global)) ||
  11                         (toString.call(x) === id) || (x[toStringTagSymbol] === 'WeakMap'))) ||
  12                         false;
  13 };