How to get the closest element from a javascript array using jQuery?

Question

I have a javascript array like this

var array1= [10,20,30,40,50];

Is there any method using which i can get the closest array element to a given number ? Ex: if i pass 26, It should return 30 ( 26 is closest to 30). If i pass 42, It should return 40.

Any thoughts ? Should i iterate thru each elements ? Is there any methods available for this in jQuery ?

Answer 1

Simple with a for loop. No jQuery magic necessary:

function getClosestNum(num, ar)
{
    var i = 0, closest, closestDiff, currentDiff;
    if(ar.length)
    {
        closest = ar[0];
        for(i;i<ar.length;i++)
        {           
            closestDiff = Math.abs(num - closest);
            currentDiff = Math.abs(num - ar[i]);
            if(currentDiff < closestDiff)
            {
                closest = ar[i];
            }
            closestDiff = null;
            currentDiff = null;
        }
        //returns first element that is closest to number
        return closest;
    }
    //no length
    return false;
}

Answer 2

If performance is a concern (very large array) and the array is ordered (as in the example), you may want to consider a Binary Search. You can probably find one pre-written for javascript but may need to modify slightly to handle your "closest" piece once the algorithm reaches the end.