JavaScript hashmap equivalent

Question

As made clear in update 3 on this answer, this notation:

var hash = {};
hash[X]

does not actually hash the object X; it actually

Answer 1

According to ECMAScript 2015 (ES6), standard JavaScript has a Map implementation. More about which could be found here.

Basic usage:

var myMap = new Map();
var keyString = "a string",
    keyObj = {},
    keyFunc = function () {};

// Setting the values
myMap.set(keyString, "value associated with 'a string'");
myMap.set(keyObj, "value associated with keyObj");
myMap.set(keyFunc, "value associated with keyFunc");

myMap.size; // 3

// Getting the values
myMap.get(keyString);    // "value associated with 'a string'"
myMap.get(keyObj);       // "value associated with keyObj"
myMap.get(keyFunc);      // "value associated with keyFunc"