Benchmark: non-unique-elements

Script Preparation code:

var data=[]; for(var i=0;i<20000;i++) data.push(i);

Tests:

Count
var cnt = {}; data.forEach(d => cnt[d] ? cnt[d]++ : cnt[d]=1); data.filter(d => cnt[d] > 1);
IndexOf
data.filter(d => data.indexOf(d) != data.lastIndexOf(d));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Count
IndexOf

Fastest: N/A

Slowest: N/A

Latest run results:

No previous 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 dive into the world of JavaScript microbenchmarks!

**Benchmark Definition**

The provided JSON represents a benchmark definition for two test cases: `Count` and `IndexOf`. The overall goal is to measure the performance of JavaScript code that performs specific operations on an array.

**Script Preparation Code**

The script preparation code is executed before running each benchmark:
```javascript
var data = [];
for (var i = 0; i < 20000; i++) data.push(i);
```
This code creates a large array `data` with 20,000 elements. This array will be used as input for both test cases.

**Html Preparation Code**

The html preparation code is empty:
```javascript
null
```
This suggests that the benchmark does not rely on any HTML-related operations or setup.

**Test Cases**

There are two test cases:

1. **Count**
```javascript
var cnt = {};
data.forEach(d => cnt[d] ? cnt[d]++ : cnt[d] = 1);
data.filter(d => cnt[d] > 1);
```
This code uses the `forEach` method to iterate over the array and increment a counter (`cnt`) for each unique element. Then, it filters out elements that have a count greater than 1.

Pros:

* Simple and concise
* Uses built-in JavaScript methods ( `forEach`, `filter` )

Cons:

* Creates an object (`cnt`) with slow lookup times

2. **IndexOf**
```javascript
data.filter(d => data.indexOf(d) != data.lastIndexOf(d));
```
This code uses the `indexOf` method to find the index of each element in the array and checks if it's equal to the last occurrence of that element.

Pros:

* Efficiently finds indices using built-in `indexOf` method

Cons:

* Uses three function calls ( `indexOf`, `lastIndexOf`, `filter` )
* May perform unnecessary work if elements are not unique

**Library Use**

There is no explicit mention of any libraries being used in the benchmark definition or test cases. However, the use of built-in JavaScript methods like `forEach` and `filter` suggests that the benchmark relies on standard library functionality.

**Special JS Feature/Syntax**

The benchmark does not appear to utilize any special JavaScript features or syntax. It only uses standard JavaScript methods and constructs.

**Alternative Approaches**

Here are some alternative approaches that could be used for these test cases:

1. **Count**
	* Instead of using `forEach` and creating an object, use a `Map` to keep track of unique elements:
```javascript
var map = new Map();
data.forEach(d => map.set(d, (map.get(d) || 0) + 1));
```
	* Use a more efficient data structure like a Trie or a prefix tree.
2. **IndexOf**
	* Instead of using `indexOf` and `lastIndexOf`, use a single pass through the array to find unique elements:
```javascript
var seen = new Set();
data.filter(d => !seen.has(d) && (seen.add(d) || true));
```
	* Use a more efficient algorithm like finding consecutive duplicates or using a hash table.

Keep in mind that these alternative approaches might have different performance characteristics and may not be suitable for all use cases. The original implementation is simple and easy to understand, but the alternatives can provide better performance or efficiency for specific scenarios.

Related benchmarks:

non-unique-elements (version: 0)

Comparing performance of: Count vs IndexOf

Created: 9 years ago by: Guest

Jump to the latest result

Count

IndexOf

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):