Benchmark: map vs forEach Chris v2

Script Preparation code:

var largeArray = Array(1000000).fill('x');

Tests:

map
largeArray.map( (value) => { });
forEach
largeArray.forEach((value) => { return value +'y';});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map
forEach

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 definition and test cases to understand what is being tested.

**What is being tested?**

The benchmark is comparing the performance of two approaches: `map()` and `forEach()`. Both methods are used to iterate over an array in JavaScript. However, they differ in their behavior when it comes to side effects and returning values.

**Options compared**

In this case, we have two options being compared:

1. `map()`: This method creates a new array with the results of applying a provided function on every element in the calling array.
2. `forEach()`: This method executes the provided callback function once for each element in an array, without creating a new array.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* `map()`:
	+ Pros: More efficient when dealing with large arrays, as it returns a new array without modifying the original. Also, it can be used with higher-order functions like `Array.prototype.reduce()` or `Array.prototype.every()`.
	+ Cons: It can create a new array in memory, which might lead to performance issues if the resulting array is very large.
* `forEach()`: 
	+ Pros: Does not require creating a new array, making it more memory-efficient. Also, it's easier to use with asynchronous code or callbacks.
	+ Cons: It does not return anything (i.e., its return value is undefined), which might be a problem if you need to process the results in some way.

**Library and purpose**

None of the test cases seem to rely on any external libraries. The `map()` and `forEach()` functions are part of the native JavaScript API, so no additional libraries are needed.

**Special JS features or syntax**

There doesn't appear to be any special JavaScript features or syntax being used in these benchmark cases. They only utilize built-in methods and basic variable assignments.

**Other alternatives**

In terms of alternative approaches for iterating over arrays, there are a few more options available:

1. `for` loops: A traditional loop that uses an index variable to iterate over each element.
2. `Array.prototype.every()`: Returns true if all elements in the array pass the provided test.
3. `Array.prototype.some()`: Returns true if at least one element passes the provided test.

Keep in mind that these alternatives might not be as efficient or convenient as using `map()` and `forEach()`, but they can provide more control over the iteration process.

**Benchmark preparation code**

The script preparation code creates a large array with 1 million elements, filled with the string 'x'. This is likely done to simulate a large dataset for the benchmark. The HTML preparation code is empty, which means that no additional setup or rendering of the HTML page is required for this benchmark.

In summary, the MeasureThat.net benchmark compares the performance of `map()` and `forEach()` when iterating over a large array. The results can help developers understand the trade-offs between these two methods when it comes to memory usage and execution speed.

Related benchmarks:

map vs forEach Chris v2 (version: 0)

performance test map vs forEach

Comparing performance of: map vs forEach

Created: 5 years ago by: Guest

Jump to the latest result

map

forEach

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):