Benchmark: unique array 3 - MeasureThat.net

Script Preparation code:

existingIds = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20];
newIds = [5,18,21,22,23,24,25,26,27]

filterUniqueValues = (id, index, array) => index === array.indexOf(id);

Tests:

array set unique
const resultingArray = Array.from(new Set(existingIds.concat(newIds)))
array filter unique
const resultingArray = existingIds.concat(newIds).filter(filterUniqueValues);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array set unique
array filter unique

Fastest: N/A

Slowest: N/A

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

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I'll break down the provided benchmark and its test cases to explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark is for JavaScript microbenchmarks on an array of numbers. It tests two different approaches: using `Array.from` with a set, and filtering unique values from an existing array.

**Script Preparation Code**

The script preparation code defines two arrays: `existingIds` and `newIds`. The purpose of this code is to create an initial dataset for the benchmark. Here's what's happening:

* `existingIds` is initialized with numbers 1-20.
* `newIds` is initialized with a subset of numbers from `existingIds`: [5, 18, 21, 22, 23, 24, 25, 26, 27].

**Benchmark Test Cases**

There are two test cases:

### Array Set Unique

```javascript
const resultingArray = Array.from(new Set(existingIds.concat(newIds)));
```

This approach uses the `Set` constructor to create a set from the concatenated array (`existingIds + newIds`). The `Array.from()` method converts this set back into an array, which is stored in the `resultingArray` variable.

**Pros:**

* This approach is likely faster because it avoids iterating over the array multiple times.
* It's a more straightforward way to remove duplicates from an array.

**Cons:**

* It can be less efficient than filtering the original array if there are many duplicate values.

### Array Filter Unique

```javascript
const resultingArray = existingIds.concat(newIds).filter(filterUniqueValues);
```

This approach uses the `concat()` method to concatenate the two arrays, and then filters out duplicates using the `filter()` method with a custom callback function (`filterUniqueValues`).

**Pros:**

* It's more flexible than using an array set because it allows for more control over the filtering process.
* It can be useful if you need to perform additional processing on each unique value.

**Cons:**

* This approach requires iterating over the array twice (once with `concat()` and once with `filter()`), which can be slower.
* The custom callback function (`filterUniqueValues`) adds complexity to the benchmark.

**Library: Set**

The `Set` constructor is a built-in JavaScript library that creates an object data structure for storing unique values. It's used in both test cases to remove duplicates from the concatenated array.

**Other Considerations**

When evaluating these approaches, consider the following factors:

* The size of the input arrays (`existingIds` and `newIds`).
* The number of duplicate values in the arrays.
* The performance characteristics of each approach on your specific use case.

**Alternative Approaches**

If you need to remove duplicates from an array but don't want to use `Set`, you can consider using other approaches:

* Using a regular array with `indexOf()` and checking for negative indices (not recommended due to its slow performance).
* Implementing a custom merge-and-check algorithm.
* Utilizing a third-party library like Lodash's `uniq` function.

However, these alternatives are generally less efficient than the `Set` approach or the filtering approach used in the benchmark.

Related benchmarks:

unique array 3 (version: 0)

Comparing performance of: array set unique vs array filter unique

Created: 6 years ago by: Registered User

Jump to the latest result

array set unique

array filter unique

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):