Binary Search with Javascript

binary_search.js

/*----
Best Case:1
Worst Case:logn
Average Case:logn
Unsuccessful:logn
-----
*/
arr=[1,2,3,4,5],val=5;

function binary_search(array,value){
    let lowerBound = 0;
    let upperBound = array.length-1;
    let index;
    while(lowerBound<=upperBound){
        let midPoint = lowerBound +Math.floor(( upperBound - lowerBound ) / 2);
        if(array[midPoint]==value){
        index=midPoint;
        break;}
        else{
        if(array[midPoint]<value)
        lowerBound=midPoint+1;
        else {
        upperBound=midPoint-1;
        }
        }
    }
    if(index!==null){
        return "bulunan değer sirasi:"+index;
    }
    return "değer bulunamadi";
}
console.log(binary_search(arr,val));