Benchmark: foreach vs map - MeasureThat.net

Script Preparation code:

var values = new Array(10000);
for (var i = 0; i < values.length; i++) values[i]=i;

Tests:

foreach
var sum = 0; values.forEach(v => sum += v );
map
var sum = 0; values.map(v => sum += v );
for of transpiled
var sum = 0; for (var _i = 0, values_1 = values; _i < values_1.length; _i++) { var v = values_1[_i]; sum += v; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
map
for of transpiled

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested.

**Benchmark Overview**

The benchmark, titled "foreach vs map", compares the performance of three different approaches to iterate over an array: `forEach`, `map`, and `for` loop with a transpiled syntax (i.e., using `of` instead of `forEach`).

**Options Being Compared**

1. **forEach**: This is a built-in JavaScript method that executes a provided function for each element in an array, without returning anything.
2. **map**: This is another built-in JavaScript method that creates a new array with the results of applying a provided function on every element in this array.
3. **For Loop with Transpiled Syntax (for...of)**: This is a syntax sugar over the traditional `for` loop, which uses the `forEach` method under the hood.

**Pros and Cons of Each Approach**

1. **forEach**:
	* Pros: Simple to use, no need to specify array length.
	* Cons: Can be slower than other approaches due to its dynamic nature (i.e., it needs to check each element).
2. **map**:
	* Pros: Returns a new array with transformed elements, can be more efficient for certain use cases.
	* Cons: Creates a new array, which can consume more memory, especially for large datasets.
3. **For Loop with Transpiled Syntax (for...of)**:
	* Pros: Often faster than `forEach` and `map`, since it's optimized for arrays with a fixed length.
	* Cons: Requires explicit declaration of variable scope, and the syntax can be less intuitive for some developers.

**Library Used**

In this benchmark, no specific library is used. The tests rely solely on built-in JavaScript methods and features.

**Special JS Feature or Syntax**

The `for...of` syntax is a relatively recent addition to JavaScript (introduced in ECMAScript 2015). It provides a concise way to iterate over arrays and other iterable objects without needing to manually increment an index variable. The `forEach` and `map` methods also use this feature internally, which is why the `for...of` syntax is used as an alternative approach.

**Other Considerations**

The benchmark measures the execution speed of each approach using a single array of 10,000 elements. The test is run in a Chrome browser on a Mac OS X 10.13.6 machine with a reported UAs that matches the raw UA string provided.

If you're interested in optimizing your JavaScript code for performance, understanding the trade-offs between these different approaches can be crucial. In general:

* Use `forEach` when you need to execute an action without returning anything and don't care about the array's length.
* Use `map` when you need to create a new array with transformed elements and don't mind consuming extra memory.
* Use a traditional `for` loop with transpiled syntax (i.e., `for...of`) when you need more control over the iteration process or want to optimize for arrays with a fixed length.

Keep in mind that this benchmark is specific to JavaScript and may not be directly applicable to other programming languages.

Related benchmarks:

foreach vs map (version: 0)

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Comparing performance of: foreach vs map vs for of transpiled

Created: 8 years ago by: Guest

Jump to the latest result

foreach

map

for of transpiled

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):