Benchmark: edit map vs slice no index optim

Script Preparation code:

window.arr = new Array(2000).fill({value: 'old'});
arr[1000] = {value: 'toReplace'};

Tests:

map
const newArr = arr.map((item) => item.value === 'toReplace' ? {value: 'new'} : item);
slice
const editIndex = arr.findIndex(item => item.value === 'toReplace'); const newArr = [ ...arr.slice(0, editIndex), {value: 'new'}, ...arr.slice(editIndex + 1), ];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map
slice

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.79 Safari/537.36

Browser/OS: Chrome 79 on Mac OS X 10.14.0

View result in a separate tab

Test name	Executions per second
map	81923.6 Ops/sec
slice	88077.1 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in the provided JSON benchmark.

**Benchmark Definition**

The benchmark is comparing two approaches to replace a value in an array: using the `Array.prototype.map()` method and using manual indexing with `Array.prototype.slice()`. The goal is to determine which approach is faster.

**Script Preparation Code**

The script preparation code creates an array `arr` with 2000 elements, fills them with an object `{value: 'old'}`, and then replaces one element at index 1000 with a new object `{value: 'toReplace'}`. This setup is used as the input for both test cases.

**Html Preparation Code**

There is no HTML preparation code provided, which means that only JavaScript performance is being measured.

**Individual Test Cases**

The two test cases are:

1. `map`: Uses the `Array.prototype.map()` method to create a new array with the same elements as the original array, but with the element at index 1000 replaced with an object `{value: 'new'}`.
2. `slice`: Uses manual indexing with `Array.prototype.slice()` to create a new array that includes all elements up to and including the one at index 1000, followed by the replacement element, and then all remaining elements.

**Pros and Cons of Each Approach**

1. `map()`:
	* Pros: concise and expressive code, easy to maintain.
	* Cons: may incur additional overhead due to creating a new array and iterating over the original array.
2. `slice()`:
	* Pros: allows for direct manipulation of the original array, can be more efficient if only a small portion of the array is being modified.
	* Cons: requires manual indexing, which can lead to errors if not implemented correctly.

**Library/Functionality Used**

In this benchmark, the following library/functionality is used:

1. `Array.prototype.map()`: a built-in JavaScript method for creating a new array with transformed elements from an existing array.
2. `Array.prototype.slice()`: a built-in JavaScript method for extracting a section of an array.

**Special JS Feature/Syntax**

None of the code snippets use any special JavaScript features or syntax that are not commonly used in everyday development.

**Other Alternatives**

Alternative approaches to replace a value in an array could include:

1. Using `forEach()` with a callback function.
2. Using `reduce()` with a custom accumulator function.
3. Using a library like Lodash's `map` function (`_.map()`) or Ramda's `map` function.

It's worth noting that the performance difference between these approaches may not be significant for small arrays, but can become more pronounced as the array size increases.

Related benchmarks:

edit map vs slice no index optim (version: 0)

Which is faster?

Comparing performance of: map vs slice

Created: 5 years ago by: Guest

Jump to the latest result

map

slice

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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