Javascript large array performance

Question

I am generating randomized string sequences from a 4 different arrays containing up to 700 strings each and now I'm worrying about the performance.

Are there any easy ways to improve perfomance of a static site like this, where you have single jquery click listener and it's randomly creating sentences based on the strings

    var first = [700_ITEMS]
    var sec = [400_ITEMS]
    $(document).ready(function() {
        $('#generate button').click(function(){
            $('#slide1 h1').html(first[Math.floor(Math.random() * first.length)]+" "+sec[Math.floor(Math.random() * sec.length)]);
        })
    });

Maybe I can read the strings somehow on the fly?

Array indexing is a constant time operation so it should not affect speed at all. The only problem might be having 1100 strings in your javascript as this of course adds a tonne to the page size and the memory allocation of the page. — Hugo Tunius
– Hugo Tunius, Commented Dec 23, 2013 at 18:12
Preemptive compilation? Or, if too intensive for the client, move to the server? — Ryan Brodie
– Ryan Brodie, Commented Dec 23, 2013 at 18:12
Are there noticeable performance issues or are you thinking there will be? — Dom
– Dom, Commented Dec 23, 2013 at 18:26
I am just wondering if I need to consider some other approach — Capuchin
– Capuchin, Commented Dec 23, 2013 at 18:30
I tend to over-analyze and prepare for problems that don't yet exist, which is pretty counterproductive. My suggestion to you is to just write code and not worry about it :). Typically, you will end up writing unused/unnecessary code, which ends up being a huge waste of time. If you happen to come across a noticeable performance change later on, then you should consider alternative options. Best of luck! — Dom
– Dom, Commented Dec 23, 2013 at 19:15

Alfabravo · Accepted Answer · 2013-12-23 18:13:19Z

1

Lookup is done once using the index, there's no performance issue unless you are doing something else to populate arrays.

The only possible improvement would be to prerender content but it kind of defeats the purpose of the algorithm.

answered Dec 23, 2013 at 18:13

Alfabravo

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Alex · Accepted Answer · 2013-12-23 18:12:49Z

0

There isn't much of a performance issue here, at all. You're not calculating all possible permutations between both arrays. It's a simple lookup to find the values, once both random numbers have been found.

answered Dec 23, 2013 at 18:12

Alex

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