Benchmark: Slice vs Filter (1111122222)

Tests:

Map
var item = 10; var index = 50; var array = Array.from({ length: 100 }).map((val, i) => i === index ? item : val);
Slice
var item = 10; var index = 50; var array = Array.from({length: 100}); var array2 = [...array.slice(0, index), ...array.slice(index + 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:

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

LLMs can make mistakes. Check important info.

I'd be happy to help you understand the JavaScript microbenchmarks on MeasureThat.net.

**Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks, which are small tests designed to measure the performance of specific code snippets. In this case, we have two benchmark definitions:

1. "Slice vs Filter (1111122222)"
2. Two individual test cases: "Map" and "Slice"

**Benchmark Definition**

The first benchmark definition is a simple script that creates an array with 100 elements using `Array.from()`, maps over the array to replace certain values, and then slices the resulting array.

```javascript
var item = 10;
var index = 50;
var array = Array.from({length: 100}).map((val, i) => i === index ? item : val);
```

This script uses two JavaScript features:

1. `Array.from()`: Creates a new array from an iterable source (in this case, an object).
2. The arrow function `i => i === index ? item : val` is used to define the mapping function.

**Options compared**

The benchmark compares two approaches:

1. **Map**: Uses the `map()` method to replace values in the array.
2. **Slice**: Uses the `slice()` method to split the array into two parts and then concatenates them using the spread operator (`...`).

**Pros and Cons**

Here are some pros and cons of each approach:

### Map

Pros:

* More concise and expressive code
* Can be faster for larger datasets, as it avoids creating intermediate arrays.

Cons:

* May have slower performance due to the overhead of mapping over the entire array.
* Requires JavaScript 5.0+ (ES6) to use arrow functions.

### Slice

Pros:

* Faster performance, as it creates only two intermediate arrays and then concatenates them.
* Works in older versions of JavaScript that don't support `map()`.

Cons:

* More verbose code
* May have slower performance for very large datasets due to the overhead of creating multiple intermediate arrays.

**Library**

There is no library used in these benchmark definitions. However, if you're using a JavaScript environment like Node.js or a browser, you may need to consider libraries like `lodash` or `underscore` for utility functions that can simplify your code.

**Special JS feature or syntax**

No special features or syntax are used in these benchmark definitions, as they only rely on standard JavaScript language features.

**Other alternatives**

If you wanted to compare other approaches, you could consider using:

* For loops instead of `map()`: `for (var i = 0; i < array.length; i++) { ... }`
* Loops with indexing: `array[index] = item; for (var i = index + 1; i < array.length; i++) { array[i] = i === array.length - 1 ? item : undefined; }`

Keep in mind that these alternatives may have different performance characteristics compared to the original map and slice approaches.

Related benchmarks:

Slice vs Filter (1111122222) (version: 0)

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>

Fastest: N/A

Slowest: N/A

No previous run results

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