I imagine this is similar to array padding, but I wonder if it can be simplified at all.
var arr = [1,2,3],
x = 5;
for (var i=0; i<x; i++) {
arr.push(x);
}
console.log(arr);
//=> [1, 2, 3, 5, 5, 5, 5, 5]
Is there any way to do this without using the for loop?
Update
Even though there are more clever solutions, the for loop seems to be the most performant.
Unless you get penalised for each line of code you write, that code is fine: succinct and very understandable.
If you do get penalised, just use:
for (var i = 0; i < x; i++) arr.push(x);
on a single line :-)
Beyond that, your best bet would be a function along the lines of:
arr = appendXCopiesOfX (arr, x);
but I don't think you're really gaining anything there since, as mentioned, there should be very little problem understanding such a small loop.
All in all, it's probably a waste of time and effort trying to improve what you currently have.