I want to check if the two arrays are identical (not content wise, but in exact order).
For example:
array1 = [1,2,3,4,5]
array2 = [1,2,3,4,5]
array3 = [3,5,1,2,4]
Array 1 and 2 are identical but 3 is not.
Is there a good way to do this in JavaScript?
So, what's wrong with checking each element iteratively?
function arraysEqual(arr1, arr2) {
if(arr1.length !== arr2.length)
return false;
for(var i = arr1.length; i--;) {
if(arr1[i] !== arr2[i])
return false;
}
return true;
}
array.join() approach -- once the function is defined. It's also less memory intensive, if that becomes an issue.
i-- statement evaluates once before the iteration starts.i-- has a double trick. :)You could compare String representations so:
array1.toString() == array2.toString()
array1.toString() !== array3.toString()
but that would also make
array4 = ['1',2,3,4,5]
equal to array1 if that matters to you
for loop is much, MUCH faster than the toString method. In my tests, the worst-case scenario for the for loop was being 20x faster. The worst case was the for loop being 80x faster. So basically don't ever use this method, it's both wrong and slow :).
array1.join() == array3.join(); but this does not check for type