Benchmark: find+splice vs map

Script Preparation code:

var array = Array.from({ length: 100000 }).map((val, i) => i);

Tests:

find+splice
const findIndex = array.findIndex(item => item === 5000); array.splice(findIndex, 1, 99999999999)
map
array.map(item => item === 5000 ? 99999999999 : item)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
find+splice
map

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36

Browser/OS: Chrome 141 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
find+splice	2268.4 Ops/sec
map	1150.2 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 provided benchmark and explain what's being tested, compared, and considered.

**Benchmark Overview**

The benchmark consists of two test cases: `find+splice` and `map`. The goal is to compare the performance of these two approaches in finding and replacing a specific element in an array.

**What's Being Tested?**

* In the `find+splice` test case:
	+ `array.findIndex(item => item === 5000)` is used to find the index of the first occurrence of the number 5000 in the array.
	+ `array.splice(findIndex, 1, 99999999999)` replaces the element at that index with a new value (99999999999).
* In the `map` test case:
	+ `array.map(item => item === 5000 ? 99999999999 : item)` creates a new array by mapping over the original array. If an element is equal to 5000, it returns 99999999999; otherwise, it returns the original value.

**Options Compared**

The two approaches are compared in terms of performance:

* `find+splice`: This approach uses the `findIndex` method followed by a call to `splice`. The `findIndex` method returns the index of the first occurrence of the specified element, and then `splice` replaces the element at that index with a new value.
* `map`: This approach uses the `map` method, which creates a new array by applying a transformation function to each element in the original array.

**Pros and Cons**

* `find+splice`:
	+ Pros: Can be more efficient if only a single replacement is needed, as it avoids creating a new array.
	+ Cons: May have higher overhead due to the use of `findIndex` and `splice`, which can lead to slower performance compared to `map`.
* `map`:
	+ Pros: More concise and expressive, as it uses a single method to create a new array with modified elements.
	+ Cons: Requires creating a new array, which can be memory-intensive if the original array is large.

**Library and Special JS Feature**

In this benchmark, no specific library or special JavaScript feature is used. However, the `Array.from` method is used in the script preparation code to create an array with 100,000 elements, which is a common pattern in modern JavaScript development.

**Other Considerations**

* Memory allocation: Both approaches allocate memory for the new array created by `map`, but the `find+splice` approach may be more efficient if only a single replacement is needed.
* Cache performance: The cache behavior of `map` can lead to slower performance compared to `find+splice`, as it involves multiple cache misses and invalidations.

**Alternatives**

Other alternatives for replacing an element in an array include:

* Using the `indexOf` method instead of `findIndex`: This is similar to `findIndex`, but returns -1 if no element matches the specified value.
* Using a library like Lodash or Ramda, which provide optimized implementations of array manipulation methods.
* Using a different data structure, such as an object or a Set, depending on the specific use case and requirements.

Related benchmarks:

find+splice vs map (version: 0)

Comparing performance of: find+splice vs map

Created: one year ago by: Guest

Jump to the latest result

find+splice

map

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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