Same function for multiple variables in an array; how to?

So I have an array with some variables. I want to define a function to be called every time an specific event happens over the variables. The function is the same for all.

Of course a simple solution would be to go one by one manually and do something as:

array[0].onevent = doThis();
array[1].onevent = doThis();
array[2].onevent = doThis();
/*and there it goes ...*/

But let's say that this will take a lot of work and the quantity of variables inside this array may vary, but all these variables share the same event and I want them as well to share the same function when this event happens.

I tried doing a for loop like:

for (item in array){
    item.onevent = doThis();
}

... but that only calls the function once for each item inside the array independently from the event.

Anyway, how can I reach a practical and efficient way to define a function for each variables event.