forEach not working when for loop does with an array of objects

Question

I have an array like so

var updates = [];

I then add stuff to the array like this

updates["func1"] = function () { x += 5 };

When I call the functions with a for loop it works as expected

for(var update in updates) {
     updates[update]();
}

But when I use the forEach it doesn't work!?

updates.forEach(function (update) {

    update();
});

forEach definitely works in my browser which is google chrome, what am I doing wrong?

Answer 1

forEach iterates over indexes not over properties. Your code:

updates["func1"] = "something";

Adds a property to an object – that incidentally is an array – not an element to an array. In fact, it's equivalent to:

updates.func1 = "something";

If you need something like an hashmap, then you can use a plain object instead:

updates = {};

updates["func1"] = "something";

And then iterate using for…in, that shouldn't be used on arrays

Or you can use Object.keys to retrieve the properties an iterate over them:

Object.keys(updates).forEach(function(key) {
    console.log(key);
});