Benchmark: Which Is the Fastest

Script Preparation code:

var arr = [];

for(var i = 0; i < 100000; i++){
  arr.push(Math.random())
}

Tests:

while loop
let i=0; while(i < arr.length) { // do stuff i++; }
// for loop
for(let i=0; i<arr.length; i++) { // do stuff }
// .forEach() method
arr.forEach((element) => { // do stuff });
// for...of loop
for(const element of arr) { // do stuff }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
while loop
// for loop
// .forEach() method
// for...of loop

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into explaining the benchmark and its various components.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmark definition on MeasureThat.net. The benchmark is named "Which Is the Fastest" and tests four different types of loops: while loop, for loop, for-of loop, and forEach method.

**Script Preparation Code**

The script preparation code is identical across all test cases:
```javascript
var arr = [];
for (var i = 0; i < 100000; i++) {
  arr.push(Math.random());
}
```
This code creates an array `arr` with 100,000 random elements.

**Html Preparation Code**

The HTML preparation code is empty (`null`) for all test cases. This suggests that the benchmark focuses solely on JavaScript execution performance, without any consideration of DOM manipulation or rendering.

**Test Cases**

There are four individual test cases, each defining a different type of loop:

1. `while loop`:
```javascript
let i = 0;
while (i < arr.length) {
  // do stuff
  i++;
}
```
2. `// for loop`:
```javascript
for (let i = 0; i < arr.length; i++) {
  // do stuff
}
```
3. `// .forEach() method`:
```javascript
arr.forEach((element) => {
  // do stuff
});
```
4. `// for...of loop`:
```javascript
for (const element of arr) {
  // do stuff
}
```
**Libraries and Special Features**

There are no explicit library dependencies mentioned in the benchmark definition.

However, it's worth noting that the benchmark uses a feature that is specific to modern JavaScript engines: the `const` keyword. The for-of loop uses `const`, which was introduced in ECMAScript 2015 (ES6).

**Pros and Cons of Each Approach**

Here are some general pros and cons of each approach:

1. **While Loop**: Pros - simple, straightforward; Cons - can be slower due to the increment operation.
2. **For Loop**: Pros - generally faster than while loops; Cons - requires manual indexing.
3. **For...Of Loop**: Pros - concise, modern syntax; Cons - may have performance overhead due to the iterator object.
4. **ForEach Method**: Pros - concise, modern syntax; Cons - may have performance overhead due to the iterator object.

**Other Alternatives**

If you want to compare these loops with other approaches, you could consider adding additional test cases, such as:

* Using `Array.prototype.forEach` (instead of the `forEach` method)
* Using a traditional `for` loop with manual indexing
* Using an array comprehension or map function
* Using a library like Lodash or Ramda for iteration

Keep in mind that these alternatives may require additional setup and modifications to the benchmark definition.

Overall, this benchmark provides a good starting point for understanding the relative performance characteristics of different JavaScript loop constructs.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.129 Safari/537.36

Browser/OS: Chrome 81 on Mac OS X 10.15.4

View result in a separate tab

Test name	Executions per second
while loop	158.5 Ops/sec
// for loop	158.2 Ops/sec
// .forEach() method	768.2 Ops/sec
// for...of loop	3518.5 Ops/sec

Related benchmarks:

Which Is the Fastest (version: 1)

While, foreach, for of, for

Comparing performance of: while loop vs // for loop vs // .forEach() method vs // for...of loop

Created: 4 years ago by: Registered User

Jump to the latest result

while loop

// for loop

// .forEach() method

// for...of loop

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):