Benchmark: foreach vs map run run run

Tests:

foreach
var obj = { items: [{ id : 1 }, { id : 2 }, { id : 3 }, { id : 4 }] } obj.items.forEach((id) => { id = id + 1; })
map
var obj = { items: [{ id : 1 }, { id : 2 }, { id : 3 }, { id : 4 }] } obj.items.map((id) => { id = id + 1; })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
map

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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Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

The provided benchmark is designed to compare the performance of two approaches: `forEach` and `map`. Both methods are used to iterate over an array and perform an operation on each element. In this case, the operation is incrementing the `id` value in each object by 1.

**Benchmark Definition**

The benchmark definition json specifies that we want to compare the performance of two approaches:

*   **`forEach`**: The `forEach` method executes a provided function once for each element in an array and returns no value.
*   **`map`**: The `map()` method creates a new array with the results of applying a provided function on every element in this array.

**Options Compared**

The two options being compared are:

1.  **`forEach`**: This method uses a callback function to execute an operation on each element in the array.
2.  **`map`**: This method also uses a callback function, but it creates a new array with the results of applying the callback function to every element.

**Pros and Cons**

Here are some pros and cons of each approach:

*   **`forEach`**:
    *   Pros:
        *   Simpler implementation: The `forEach` method has a simpler syntax and is easier to understand for those who are familiar with JavaScript.
        *   Better performance in older browsers: `forEach` is generally faster than `map()` in older browsers due to the way it handles iteration.
    *   Cons:
        *   Creates side effects: The `forEach` method executes the callback function on each element, which can create side effects if not handled carefully.
*   **`map`**:
    *   Pros:
        *   Returns a new array: The `map()` method returns a new array with the results of applying the callback function to every element, making it easier to process the output.
        *   Easier parallelization: Since `map()` returns an array, it's easier to parallelize the execution across multiple processors or threads.
    *   Cons:
        *   Slower performance in older browsers: `map()` is generally slower than `forEach` in older browsers due to the way it handles iteration.

**Other Considerations**

When choosing between `forEach` and `map`, consider the following factors:

*   **Side effects**: If you need to execute an operation on each element without creating side effects, `forEach` might be a better choice.
*   **Parallelization**: If you want to parallelize the execution of the callback function across multiple processors or threads, `map()` is generally easier and more efficient.

**Library/Functionality**

There are no libraries or external functions used in this benchmark. The test cases only use built-in JavaScript methods (`forEach` and `map`) and a simple object with array elements to perform the operations.

**Special JS Features/Syntax**

This benchmark does not involve any special JavaScript features or syntax beyond what's normally available in most modern browsers. It focuses on comparing two common iteration approaches.

In conclusion, this benchmark provides a useful comparison of the performance differences between `forEach` and `map` methods for iterating over arrays. By understanding the pros and cons of each approach, developers can make informed decisions about which method to use in their codebases.

Related benchmarks:

foreach vs map run run run (version: 0)

Comparing performance of: foreach vs map

Created: 7 years ago by: Guest

Jump to the latest result

foreach

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):