True hash maps / bare objects

hash-maps.js

// See: http://ryanmorr.com/true-hash-maps-in-javascript/
// This creates a 'bare object' that can be used as a true hash map.
// Safe to use `for...in` because it doesn't inherit `Object.prototype`

var map = Object.create(null);

map instanceof Object; // false
Object.prototype.isPrototypeOf(map); // false
Object.getPrototypeOf(map); // null