Benchmark: map vs forEach/push (10 000 elements)

Script Preparation code:

window.arr = Array.from({ length: 10000 }, (_, i) => `Option ${i + 1}`);

Tests:

map
const newArr = window.arr.map(element => ({ label: element, value: element })); newArr.unshift({ label: 'User', value: 'User' });
forEach/push
const newArr = []; newArr.push({ label: 'User', value: 'User' }) window.arr.forEach(element => { newArr.push({ label: element, value: element }) })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map
forEach/push

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
map	16004.7 Ops/sec
forEach/push	16426.3 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark compares two approaches to transform an array of strings into a new array with additional elements:

1. `map` method
2. Using `forEach` loop to push new elements into an initial empty array.

**Options Compared**

The two options being compared are:

* **`map` method**: A built-in JavaScript method that creates a new array by executing a provided function on each element of the original array.
* **Using `forEach` loop**: This approach uses a traditional loop to iterate over the original array and push new elements into an initial empty array.

**Pros and Cons**

**`map` Method:**

Pros:

* More concise and expressive code
* Less error-prone, as it avoids manual looping and indexing
* Optimized for performance by using a single pass through the original array

Cons:

* Can be slower due to the overhead of creating a new array and executing the provided function on each element
* May not perform well with large or complex data sets

**Using `forEach` Loop:**

Pros:

* More control over the transformation process, as it allows for manual looping and indexing
* Can be faster for small to medium-sized data sets due to reduced overhead compared to `map`
* Easier to debug and optimize for performance

Cons:

* Requires more code and is less concise
* More prone to errors due to manual looping and indexing

**Other Considerations**

* **Array Initialization**: The benchmark uses an initial empty array (`[]`) as the target for pushing new elements using the `forEach` loop. This can affect performance, as it requires allocating memory for a new array.
* **String Concatenation**: In the `map` method, the transformation function concatenates strings to create a new object with both the original string and its value. While this is not explicitly mentioned in the benchmark, it's worth noting that string concatenation can be slow due to the overhead of creating temporary strings.

**Library Usage**

None of the provided code snippets use any external libraries or modules beyond built-in JavaScript features. However, if we were to consider the `Array.from` method used in the script preparation code, it's a modern JavaScript feature introduced in ECMAScript 2015 (ES6).

**Special JS Features/Syntax**

The benchmark uses the following special features:

* **Arrow Functions**: The transformation function in the `map` method is an arrow function (`element => ({ label: element, value: element })`). Arrow functions are a shorthand way of defining small anonymous functions and can improve code readability.
* **Template Literals**: In the `forEach` loop, strings are concatenated using template literals (`"Option ${i + 1}"`). Template literals provide a more modern way of string formatting and can improve code readability.

**Other Alternatives**

For transforming arrays in JavaScript, other approaches could include:

* Using `reduce()` method
* Implementing a custom looping solution (e.g., using `for` loop or `while` loop)
* Utilizing third-party libraries like Lodash or Underscore.js for array manipulation

Keep in mind that the choice of approach depends on the specific requirements and constraints of your project, such as performance, code readability, and maintainability.

Related benchmarks:

map vs forEach/push (10 000 elements) (version: 0)

Comparing performance of: map vs forEach/push

Created: 3 years ago by: Guest

Jump to the latest result

map

forEach/push

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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