binary-search.js

function binarySearch(arr, item) {
    let startIndex = 0;
    let endIndex = arr.length - 1;

    while (startIndex < endIndex) {
        let middleIndex = Math.floor((startIndex + endIndex) / 2);

        if (arr[middleIndex] === item) {
            return `Found at index ${middleIndex}`;
        }

        if (arr[middleIndex] < item) {
            startIndex = middleIndex + 1;
        } else {
            endIndex = middleIndex - 1;
        }
    }

    return "Not Found";
}

console.log(binarySearch([5, 10, 20, 30, 40], 30));
//output: Found at index 3