text: "use strict"
  
  // We have an ES6 Map available, return the native instance
  if(typeof global.Map !== 'undefined') {
    module.exports = global.Map;
    module.exports.Map = global.Map;
  } else {
    // We will return a polyfill
    var Map = function(array) {
      this._keys = [];
      this._values = {};
  
      for(var i = 0; i < array.length; i++) {
        if(array[i] == null) continue;  // skip null and undefined
        var entry = array[i];
        var key = entry[0];
        var value = entry[1];
        // Add the key to the list of keys in order
        this._keys.push(key);
        // Add the key and value to the values dictionary with a point
        // to the location in the ordered keys list
        this._values[key] = {v: value, i: this._keys.length - 1};
      }
    }
  
    Map.prototype.clear = function() {
      this._keys = [];
      this._values = {};
    }
  
    Map.prototype.delete = function(key) {
      var value = this._values[key];
      if(value == null) return false;
      // Delete entry
      delete this._values[key];
      // Remove the key from the ordered keys list
      this._keys.splice(value.i, 1);
      return true;
    }
  
    Map.prototype.entries = function() {
      var self = this;
      var index = 0;
  
      return {
        next: function() {
          var key = self._keys[index++];
          return {
            value: key !== undefined ? [key, self._values[key].v] : undefined,
            done: key !== undefined ? false : true
          }
        }
      };
    }
  
    Map.prototype.forEach = function(callback, self) {
      self = self || this;
  
      for(var i = 0; i < this._keys.length; i++) {
        var key = this._keys[i];
        // Call the forEach callback
        callback.call(self, this._values[key].v, key, self);
      }
    }
  
    Map.prototype.get = function(key) {
      return this._values[key] ? this._values[key].v : undefined;
    }
  
    Map.prototype.has = function(key) {
      return this._values[key] != null;
    }
  
    Map.prototype.keys = function(key) {
      var self = this;
      var index = 0;
  
      return {
        next: function() {
          var key = self._keys[index++];
          return {
            value: key !== undefined ? key : undefined,
            done: key !== undefined ? false : true
          }
        }
      };
    }
  
    Map.prototype.set = function(key, value) {
      if(this._values[key]) {
        this._values[key].v = value;
        return this;
      }
  
      // Add the key to the list of keys in order
      this._keys.push(key);
      // Add the key and value to the values dictionary with a point
      // to the location in the ordered keys list
      this._values[key] = {v: value, i: this._keys.length - 1};
      return this;
    }
  
    Map.prototype.values = function(key, value) {
      var self = this;
      var index = 0;
  
      return {
        next: function() {
          var key = self._keys[index++];
          return {
            value: key !== undefined ? self._values[key].v : undefined,
            done: key !== undefined ? false : true
          }
        }
      };
    }
  
    // Last ismaster
    Object.defineProperty(Map.prototype, 'size', {
      enumerable:true,
      get: function() { return this._keys.length; }
    });
  
    module.exports = Map;
    module.exports.Map = Map;
  }