Benchmark: non-unique-elements

Tests:

Count
var data = [6, 1, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 5, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 8]; var cnt = {}; data.forEach(d => cnt[d] ? cnt[d]++ : cnt[d]=1); data.filter(d => cnt[d] > 1);
IndexOf
var data = [6, 1, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 5, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 8]; 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 break down the provided benchmark and explain what is being tested.

**Benchmark Overview**

The benchmark measures the performance of two different JavaScript functions: `Count` and `IndexOf`. The test cases are designed to compare the execution speed of these functions on an array of numbers.

**Test Case 1: Count**

This test case uses a library called **Lodash**, which is a popular JavaScript utility library. In this specific test, Lodash is used for its `forEach` method and object manipulation capabilities.

The benchmark definition code:
```javascript
var data = [6, 1, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 5, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 8];
var cnt = {};
data.forEach(d => cnt[d] ? cnt[d]++ : cnt[d]=1);
data.filter(d => cnt[d] > 1);
```
The `Count` function uses a simple object to count the occurrences of each number in the array. The `forEach` method is used to iterate over the array, and for each iteration, it updates the object `cnt` with the current count.

**Test Case 2: IndexOf**

This test case does not use any external libraries. It uses a built-in JavaScript method called **indexOf()**, which returns the index of the first occurrence of a specified value in an array.

The benchmark definition code:
```javascript
var data = [6, 1, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 5, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 8];
data.filter(d => data.indexOf(d) != data.lastIndexOf(d));
```
The `IndexOf` function uses the `indexOf()` method to find the index of each number in the array. The `filter()` method is then used to create a new array containing only the numbers that have different indices for their first and last occurrences.

**Comparison**

The two test cases are designed to compare the performance of different approaches to counting the occurrences of numbers in an array: using an object with `forEach` vs. using the built-in `indexOf()` method.

**Pros and Cons**

* **Using an object with `forEach`:**
	+ Pros:
		- Simple and efficient for small arrays
		- Can handle duplicate values
	+ Cons:
		- May be slower due to the overhead of object manipulation
* **Using `indexOf()`:**
	+ Pros:
		- Fast and efficient for large arrays
	+ Cons:
		- May not work correctly for arrays with duplicate values

**Other Considerations**

* The benchmark uses a relatively small array of numbers, which may affect the results. Larger arrays may require more time to execute.
* The `Count` function uses an object to store the counts, while the `IndexOf` function uses the built-in `indexOf()` method. This difference in approach may impact performance.

**Alternatives**

Other alternatives for counting occurrences or finding indices in an array include:

* Using `Array.prototype.reduce()`
* Using a simple loop with index variables
* Using other libraries or frameworks that provide optimized implementations of these operations

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):