Benchmark: Array iter vs set iter (test order change)

Array iter vs set iter (test order change) (version: 0)

Iterate over an array vs iterating over a set.

Comparing performance of: native loop arr: few items vs for of set: few items vs for of arr: few items vs native iter set: few items vs for of arr: many items vs for of set: many items vs native loop arr: many items vs native iter set: many items

Created: 3 years ago by: Registered User

Jump to the latest result

Script Preparation code:

var fewItemArr = [1, 2, 3];
var fewItemSet = new Set(fewItemArr);
var manyItemArr = Array.from({ length: 1000 }, (_, i) => i);
var manyItemSet = new Set(manyItemArr);

Tests:

native loop arr: few items
let result = 0; for (let i = fewItemArr.length; i--;) { result += fewItemArr[i]; }
for of set: few items
let result = 0; for (const item of fewItemSet) { result += item; }
for of arr: few items
let result = 0; for (const item of fewItemArr) { result += item; }
native iter set: few items
let result = 0; let val = null; const iter = fewItemSet.values(); while (!(val = iter.next()).done) { result += val.value; }
for of arr: many items
let result = 0; for (const item of manyItemArr) { result += item; }
for of set: many items
let result = 0; for (const item of manyItemSet) { result += item; }
native loop arr: many items
let result = 0; for (let i = manyItemArr.length; i--;) { result += manyItemArr[i]; }
native iter set: many items
let result = 0; let val = null; const iter = manyItemSet.values(); while (!(val = iter.next()).done) { result += val.value; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
native loop arr: few items
for of set: few items
for of arr: few items
native iter set: few items
for of arr: many items
for of set: many items
native loop arr: many items
native iter set: many items

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one month ago):

LLMs can make mistakes. Check important info.

I'll break down the benchmark test and its components.

**Benchmark Test Overview**

The test measures the performance of iterating over arrays versus sets in JavaScript, specifically comparing:

1. Using `for` loops
2. Using the `for...of` loop syntax
3. Using a `while` loop with a `values()` iterator

**Script Preparation Code**

The script preparation code creates two types of data structures: an array (`fewItemArr`) and a set (`fewItemSet`). The array has only a few items, while the set is converted from the same array to demonstrate performance differences.

```javascript
var fewItemArr = [1, 2, 3];
var fewItemSet = new Set(fewItemArr);

var manyItemArr = Array.from({ length: 1000 }, (_, i) => i);
var manyItemSet = new Set(manyItemArr);
```

**Iteration Approaches**

The test compares four iteration approaches:

1. **Native Loop**: Using a `for` loop with the index variable.
```javascript
let result = 0;
for (let i = fewItemArr.length; i--;) {
  result += fewItemArr[i];
}
```
2. **For...of Loop on Array**: Using the `for...of` loop syntax to iterate over an array.
```javascript
let result = 0;
for (const item of fewItemArr) {
  result += item;
}
```
3. **For...of Loop on Set**: Using the `for...of` loop syntax to iterate over a set.
```javascript
let result = 0;
for (const item of fewItemSet) {
  result += item;
}
```
4. **Native Iteration with while and values()**: Using a `while` loop with a `values()` iterator to iterate over a set.
```javascript
let result = 0;
let val = null;
const iter = fewItemSet.values();
while (!(val = iter.next()).done) {
  result += val.value;
}
```
**Performance Results**

The test provides performance results for each iteration approach, measured by the number of executions per second (ExecutionsPerSecond). The results indicate that:

* Using `for...of` loops on arrays and sets is generally faster than native loops.
* Native iteration with a `while` loop and `values()` iterator can be slower than using `for...of` loops.

**Implications**

This benchmark test highlights the performance benefits of using `for...of` loops when iterating over arrays and sets. It also shows that native iteration can sometimes be less efficient, but may offer more control or flexibility in certain scenarios.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.66 Safari/537.36

Browser/OS: Chrome 87 on Windows

View result in a separate tab

Test name	Executions per second
native loop arr: few items	2355944.8 Ops/sec
for of set: few items	8464252.0 Ops/sec
for of arr: few items	8931765.0 Ops/sec
native iter set: few items	8418329.0 Ops/sec
for of arr: many items	763004.1 Ops/sec
for of set: many items	403391.9 Ops/sec
native loop arr: many items	9680.0 Ops/sec
native iter set: many items	400318.5 Ops/sec

Related benchmarks:

Array iter vs set iter (test order change) (version: 0)

Iterate over an array vs iterating over a set.

Comparing performance of: native loop arr: few items vs for of set: few items vs for of arr: few items vs native iter set: few items vs for of arr: many items vs for of set: many items vs native loop arr: many items vs native iter set: many items

Created: 3 years ago by: Registered User

Jump to the latest result

native loop arr: few items

for of set: few items

for of arr: few items

native iter set: few items

for of arr: many items

for of set: many items

native loop arr: many items

native iter set: many items

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one month ago):