In javascript how do I call a function dynamically added to an object

Question

Keeping up with the Javascript learning effort. I am looking at the following code which aims to add functions to an object keeping them unique, something like adding callback functions to an event kind of thing.

var store = {
    nextId: 1,
    cache: {},
    add: function(fn) {
        if(!fn.id){
            fn.id = store.nextId++;
            return !!(store.cache[fn.id] = fn);
        }
    }
};

The code works well but now I would like to execute those functions and I haven't been able to figure that part out.

So far I have tried to call the two functions directly as methods of the store.cache object which gives me the error "Object# has no method 'blah'". Also I tried doing a loop as if store.cache was an array of functions but that didn't work either.

Thanks for any help.

The function can be invoked like so: store.cache[1](), store.cache[2](), etc. — Šime Vidas
– Šime Vidas, Commented Aug 7, 2012 at 16:14

hvgotcodes · Accepted Answer · 2012-08-07 16:15:16Z

1

I would add a method to store, something like this

executeFunction: function(id) {
   var fn = store.cache[id];
   if (fn) return fn();
   else throw 'could not find function for id...';
}

and then you can just do

var result = store.executeFunction(someId);

you can expand upon that so that your executeFunction takes the context (scope) and arguments which should be applied to the function.

answered Aug 7, 2012 at 16:15

hvgotcodes

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Comments

DerWaldschrat · Accepted Answer · 2012-08-07 16:17:29Z

0

There are easier ways to store a list of callbacks, but to solve your problem just do:

var i;
for (i in store.cache) {
    store.cache[i]();
}

for (i in variable) cycles through all the properties of variable, and i gets the key of the property.

answered Aug 7, 2012 at 16:17

DerWaldschrat

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