Consecutively return a random item from a JavaScript array

Alex Carpenter on March 11, 2019

View this post on The other week I was working on a side project where I needed to consecutively return a random item from an arr... [Read Full]
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Another way to do it is to create an array that contains every item except the current one, and then take a random item from that:

btn.addEventListener('click', function() {
  var otherFruits = fruit.filter(function(item) { return item !== currentItem });
  currentItem = randomItem(otherFruits);
}, false);

Definitely, but it seemed more performant to not create a new array using filter on every click.


It's hard to know, right? I would guess the average performance for my version is worse, for the reason you mentioned. But the worst-case performance for your version is worse, because in theory that loop can spin and spin until the random number generator picks a different fruit.

But really, the performance costs we're talking about aren't important, if they only happen once per human click interval. I'd favor readability... if I could just decide which one was more readable.

... Anyway, I just think it's fun to see multiple ways to do things.

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