Benchmark: For vs foreach - MeasureThat.net

Tests:

for loop
var arr = []; for (var i = 0; i<10000; i++) { arr.push(i); } var sum = 0; for (var j = 0; j < arr.length; j++) { sum = sum + j; }
for each
var arr = []; for (var i = 0; i<10000; i++) { arr.push(i); } var sum = 0; arr.forEach(function(num) { sum = sum + num; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for loop
for each

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Linux

View result in a separate tab

Test name	Executions per second
for loop	26604.4 Ops/sec
for each	10775.4 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll explain the benchmark in detail.

**Benchmark Overview**

The benchmark compares two approaches for iterating over an array of numbers: traditional `for` loops and `forEach` method. The goal is to measure which approach is faster.

**Options Compared**

There are two options compared:

1. **Traditional `for` loop**: This approach uses a manual counter variable (`i`) to iterate over the array, with explicit bounds checking.
2. **`forEach` method**: This approach uses the `Array.prototype.forEach()` method, which iterates over the array using a callback function.

**Pros and Cons of Each Approach**

1. **Traditional `for` loop**:
	* Pros: More control over iteration, can be optimized for specific use cases.
	* Cons: Requires manual bounds checking, can lead to index-related errors if not implemented carefully.
2. **`forEach` method**:
	* Pros: Convenient and concise syntax, reduces the risk of index-related errors.
	* Cons: May introduce overhead due to function call overhead, and may not be optimized for specific use cases.

**Library and Purpose**

In this benchmark, there is no explicit library mentioned. However, the `Array.prototype.forEach()` method is a part of the ECMAScript standard (ES6+) and is widely supported by modern JavaScript engines.

**Special JS Feature or Syntax**

There are no special JavaScript features or syntax used in this benchmark. The code uses standard ES5 features and syntax.

**Other Alternatives**

If you're looking for alternatives to `forEach`, some options include:

1. **`map()`**: Can be used to transform the array while iterating, but may not be as suitable for simple iteration use cases.
2. **`reduce()`**: Can be used to accumulate values from an array, but may not be as efficient as `forEach` for pure iteration use cases.

**Benchmark Preparation Code**

The benchmark preparation code is empty, which means that the script will start execution from scratch with each test case.

**Individual Test Cases**

There are two test cases:

1. **"for loop"`**: This test case measures the performance of a traditional `for` loop approach.
2. **"for each"`**: This test case measures the performance of the `forEach` method approach.

The benchmark results show that the Chromium 52 browser performs better on the "for loop" test case, with an average execution rate of approximately 11,066.45 executions per second. The same browser performs worse on the "for each" test case, with an average execution rate of approximately 4,391.07 executions per second.

Keep in mind that these results may vary depending on the specific use case and environment in which the benchmark is run.

Related benchmarks:

For vs foreach (version: 0)

Comparing performance of: for loop vs for each

Created: 9 years ago by: Guest

Jump to the latest result

for loop

for each

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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