Benchmark: Array loop vs foreach vs map2

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 1024; i++) {
      arr.push(Math.random());
    }
  let idx = 0;
    function someFn(i) {
      return i * 3 * 8 + arr[idx++ & 1023];
    }

Tests:

foreach
arr.forEach(someFn)
for
for (const it of arr) { someFn(it); }
map
arr.map(someFn)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

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Let's dive into the explanation of the provided benchmark.

**Benchmark Description**

The benchmark tests three different approaches to iterate over an array: `forEach`, `for` loop, and `map`. The iteration is performed on an array of 1024 random numbers. The function `someFn` is applied to each element of the array, which performs a simple calculation involving multiplication and modulo operations.

**Options Compared**

The benchmark compares three different approaches:

1. **forEach**: Uses the `forEach` method, which calls the provided callback function once for each element in the array.
2. **for loop**: Uses a traditional `for` loop to iterate over the array elements.
3. **map**: Uses the `map` method, which creates a new array by applying the provided callback function to each element of the original array.

**Pros and Cons**

1. **forEach**:
	* Pros: Easy to use, concise code.
	* Cons: Can be slower due to the overhead of the method call, and may not be suitable for large arrays.
2. **for loop**:
	* Pros: Control over iteration, no overhead from method calls.
	* Cons: More verbose code, requires manual indexing.
3. **map**:
	* Pros: Creates a new array with the transformed elements, easy to read.
	* Cons: May incur additional memory allocation and copying costs.

**Library and Purpose**

None of the provided benchmarks use any external libraries or frameworks.

**Special JS Feature/Syntax**

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

**Alternative Approaches**

Other alternative approaches to iterate over an array include:

1. **Array.prototype.reduce()**: Instead of using `forEach` or `for`, the array can be reduced by applying a callback function that accumulates the results.
2. **Arrow functions**: Arrow functions can be used as callbacks for `forEach` and `map`.
3. **Generators**: Generators can be used to iterate over arrays in a more functional programming style.

In summary, the benchmark provides a simple and concise way to compare the performance of different iteration approaches in JavaScript, helping developers understand the trade-offs between various methods.

Related benchmarks:

Array loop vs foreach vs map2 (version: 0)

Comparing performance of: foreach vs for vs map

Created: 4 years ago by: Registered User

Jump to the latest result

foreach

for

map

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):