Benchmark: Array loop for() vs for(in) vs foreach

Script Preparation code:

var temp=0;   
var arr = [];
    for (var i = 0; i < 10000; i++) {
      arr[i] = i;
    }

Tests:

foreach
var temp=0; arr.forEach(function (item){ temp+=item; })
for
var temp=0; for (var i = 0, len = arr.length; i < len; i++) { temp+=arr[i]; }
for(in)
var temp=0; for(let n in arr) temp+=arr[n];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
for(in)

Fastest: N/A

Slowest: N/A

Latest run results:

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

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**Overview**

The provided JSON represents a JavaScript microbenchmarking test case on MeasureThat.net, which compares the performance of three different iteration methods: `forEach()`, traditional `for` loops, and `for...in`. The goal is to identify which method provides the best performance for array iterations.

**Benchmark Definition**

The benchmark definition specifies three script preparation codes:

1. `forEach()`: This code uses the `forEach()` method to iterate over the array, incrementing a temporary variable (`temp`) by each item's value.
2. Traditional `for` loop: This code uses a traditional `for` loop with an index variable (`i`) to iterate over the array, also incrementing `temp`.
3. `for...in`: This code uses the `for...in` loop syntax to iterate over the array's properties (i.e., its indices), again incrementing `temp`.

**Options Comparison**

The three options are compared in terms of performance:

1. **`forEach()`**: Pros:
	* Easy to read and maintain, as it abstracts away the iteration logic.
	* Works with most modern browsers and environments.
2. **Traditional `for` loop**:
	* Pros:
		+ Direct control over iteration variables and increment logic.
		+ Can be optimized for specific use cases (e.g., using `i` instead of `n`).
3. **`for...in`**: Pros:
	* Similar to traditional `for` loops in terms of performance and control.

Cons:

1. **`forEach()`**:
	* May incur overhead due to the method call.
	* May not work with older browsers or environments that don't support `forEach()`.
2. **Traditional `for` loop**:
	* Requires manual management of iteration variables and increment logic.
	* Can be error-prone if not optimized correctly.
3. **`for...in`**:
	* May incur overhead due to the use of the `in` operator.
	* May not work with arrays that have non-numeric properties.

**Library and Special JS Features**

In this benchmark, no specific libraries or special JavaScript features are used beyond the built-in array methods. The test focuses on comparing basic iteration methods.

**Alternatives**

For similar benchmarking purposes, you can consider using other alternatives:

1. **Benchmarking frameworks**: Tools like Benchmark.js, Microbenchmark, or JSPerf can provide more advanced features and flexibility for creating and running microbenchmarks.
2. **Other iteration methods**: Additional iteration methods, such as `filter()`, `map()`, or `reduce()`, could be compared in a separate benchmark to evaluate their performance characteristics.

Keep in mind that the specific requirements and goals of your project may influence the choice of alternative tools or frameworks.

Related benchmarks:

Array loop for() vs for(in) vs foreach (version: 0)

Compare for(index), for(in) and forEach()

Comparing performance of: foreach vs for vs for(in)

Created: 5 years ago by: Registered User

Jump to the latest result

foreach

for

for(in)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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