What is the most efficient way to create map of functions to arguments?

Question

I want to create a map of functions to its argument. This map will be updated dynamically. Finally all the functions will be called with their corresponding arguments.

Answer 1

Until there's a native cross-browser solution for having objects as keys, you could always implement your own solution. Here's an example of what you could do. In the code below, the ObjectMap will store a generated key as a property of the object that needs to serve as a key. The property name that is used to store the key on the object is randomized to reduce possible conflicts. The map implementation can then use this property's value to retrieve the key on the object and then retrieve it's associated value.

JSPERF: http://jsperf.com/object-map

function ObjectMap() {
    this.key = 0;
    //you should implement a better unique id algorithm
    this.mapId = '_' + Math.floor(Math.random() * 10000);
    this.data = {};
}

ObjectMap.prototype = {
    set: function (object, value) {
        var key = ++this.key;

        if (object[this.mapId]) {
            return;
        }

        object[this.mapId] = key;
        this.data[key] = value;
    },

    get: function (object) {
        var key = object[this.mapId];

        return key? this.data[key] : null;
    },

    remove: function (object) {
        var key = object[this.mapId];
        if (!key) {
            return;
        }
        delete this.data[key];
        delete object[key];
    }
};

function a() {}

var map = new ObjectMap();

map.set(a, 'test');

console.log(map.get(a)); //test