Binary Search implementation in JavaScript

binary-search.js

function binarySearch(arr, value, start = 0, end = arr.length - 1) {
	if (start > end) {
		return -1;
	}
	const middleElementIndex = Math.floor((end - start) / 2) + start;
	const middleElementValue = arr[middleElementIndex];

	if (value === middleElementValue) {
		return middleElementIndex;
	}

	if (value < middleElementValue) {
		return binarySearch(arr, value, start, middleElementIndex - 1);
	} else {
		return binarySearch(arr, value, middleElementIndex + 1, end);
	}
}

/*
const testArray = [ 1, 3, 5, 6, 8, 99 ];
if (binarySearch(testArray, 8) !== testArray.indexOf(8)) {
	throw new Error(`BinarySearch test failed`);	
}
*/