Question

I had a problem that was making the original array to change, the curious thing is that adding arr.join("...").split("...") seems to prevent this:

A little background:

• my script creates and adds stuff to an array
• this array initialized empty like arr=[]
• the things are added passing arr[index] = "..."
• then I want to have a copy of the arr but sorted
• when I do the sorting, the orignial arr is modified

Here is a simplified version of what is going on:

var arr=[], sorted;

arr[0] = "hello";
arr[1] = "world";

//buggy, the original is sorted
//sorted = arr.sort(function(a,b){return (a.length-b.length);});

sorted = arr.join("improbableCollision").split("improbableCollision").sort(function(a,b){return (a.length-b.length);});

• Why adding .join("*").split("*") solves the problem?
• What was causing the problem?
• Is there a more elegant way to fix this?

For the full script, check this jsFiddle

Answer 1

To sort without all that joining and splitting, copy the array with slice or concat:

var sorted = arr.slice(0).sort()