Run results for: Nj9ZJ^FuK4AJ#wKE

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36

Browser: Chrome 96

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
fori	103.2 Ops/sec
lazy range with index number	518.2 Ops/sec
range with index number	327.2 Ops/sec
range without index number	1383.0 Ops/sec
lazy range without index number	516.4 Ops/sec

Script Preparation code:

var length = 100000;

function* range(from, to, step = 1) {
    if (!step) return;
    if (!to) to = from, from = 0;

    if (from < to && step > 0) {
        while (from < to) {
            yield from;
            from += step;
        }
    } else if (from > to && step < 0) {
        while (from > to) {
            yield from;
            from += step;
        }
    }
}

function* range_undefined(from, to, step = 1) {
    if (!step) return;
    if (!to) to = from, from = 0;

    if (from < to && step > 0) {
        while (from < to) {
            yield;
            from += step;
        }
    } else if (from > to && step < 0) {
        while (from > to) {
            yield;
            from += step;
        }
    }
}

Tests:

fori
for (let i = 0; i < length; i++) {}
lazy range with index number
for (const i of range(length)) {}
range with index number
for (const i of Array.from(Array(length).keys())) {}
range without index number
for (const i of Array.from(Array(length))) {}
lazy range without index number
for (const i of range_undefined(length)) {}

Run results for: Nj9ZJ^FuK4AJ#wKE

Compare loop performance

fori

lazy range with index number

range with index number

range without index number

lazy range without index number