Run results for: Array find middle

Run details:

User agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:103.0) Gecko/20100101 Firefox/103.0

Browser: Firefox 103

Operating system: Windows 8.1

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
function 1	428923.5 Ops/sec
function 2	2408855.2 Ops/sec

Script Preparation code:

function test1(array) {
	for (let i = 0; i < array.length; i++) {
		let lsum = array.slice(0, i).reduce((carry, value) => carry + value, 0);
		let rsum = array.slice(i).reduce((carry, value) => carry + value, 0);
		if (lsum === rsum) return i;
	}
	return -1;
}

function test2(array) {
	let sum = array.reduce((carry, value) => carry + value, 0);
	for (let i = 0, lsum = 0, rsum = sum; i < array.length; i++, lsum += array[i - 1], rsum -= array[i - 1]) {
		if (lsum === rsum) {
			return i;
		}
	}
	return -1;
}

Tests:

function 1
test1([1, 5, -8, 0, -2]); test1([-2, 2, 5]); test1([1, 1, 1, 1, -4]);
function 2
test2([1, 5, -8, 0, -2]); test2([-2, 2, 5]); test2([1, 1, 1, 1, -4]);

Run results for: Array find middle

function 1

function 2