Benchmark: lodash unionWith vs Set for merging without duplicates test 2

HTML Preparation code:

<script src='https://cdn.jsdelivr.net/npm/lodash@4.17.10/lodash.min.js'></script>

Tests:

Set&map
var first = [ {'id': 2, 'FirstName': 'Jim'}, {'id': 4, 'FirstName': 'Tom'}, {'id': 5, 'FirstName': 'George'} ]; var second = [ {'id': 2, 'FirstName': 'Jim'}, {'id': 7, 'FirstName': 'Tom'}, {'id': 8, 'FirstName': 'George'} ]; const ids = new Set( [...first.map((identifiedFile) => identifiedFile.id)] ); second.forEach((identifiedFile) => { if (!ids.has(identifiedFile.id)) first.push(identifiedFile); }); return first
unionWith2
var first = [ {'id': 2, 'FirstName': 'Jim'}, {'id': 4, 'FirstName': 'Tom'}, {'id': 5, 'FirstName': 'George'} ]; var second = [ {'id': 2, 'FirstName': 'Jim'}, {'id': 7, 'FirstName': 'Tom'}, {'id': 8, 'FirstName': 'George'} ]; return _.unionWith(first, second, _.isEqual);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Set&map
unionWith2

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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Let's dive into the benchmark.

**What is being tested?**

The provided JSON represents two test cases that compare the performance of merging arrays without duplicates using two different approaches:

1.  **Set and map**: This approach uses JavaScript's built-in `Set` data structure to store unique IDs from the first array (`first`) and then iterates over the second array (`second`). If an ID is not present in the set, it adds the corresponding object from the second array to the first array.
2.  **Lodash `unionWith`**: This approach uses the `lodash` library's `unionWith` function, which merges two arrays and removes duplicates based on a provided equality function (`_.isEqual`).

**Options being compared:**

The benchmark is comparing these two approaches:

*   Set and map (using JavaScript's built-in `Set`)
*   Lodash `unionWith`

**Pros and Cons of each approach:**

### Set and Map

Pros:

*   **Efficient**: Using a `Set` to store unique IDs can be efficient, especially when dealing with large datasets.
*   **JavaScript native**: This approach is a built-in part of JavaScript, making it easy to implement.

Cons:

*   **Performance overhead**: Creating a `Set` and iterating over it might incur some performance overhead compared to using an optimized library like Lodash.
*   **Limited error handling**: If the equality function used in `_.isEqual` returns false for any IDs, the approach may not work as expected.

### Lodash `unionWith`

Pros:

*   **Optimized implementation**: The `lodash` library is likely to have a highly optimized implementation of the `unionWith` function.
*   **Robust error handling**: The equality function in `_.isEqual` can handle various cases, ensuring that duplicates are correctly removed.

Cons:

*   **Dependency on Lodash**: This approach relies on the `lodash` library being included or loaded, which might add extra overhead to the execution time.
*   **Potential memory leaks**: If not used carefully, this approach could lead to memory leaks due to the creation of unnecessary objects.

**Library and its purpose:**

The provided benchmark uses the Lodash library. Lodash is a popular JavaScript utility library that provides a wide range of functions for tasks such as:

*   Array manipulation (e.g., `unionWith`, `differenceBy`)
*   Object manipulation (e.g., `merge`, `pick`)
*   Functionality extension (e.g., `partial`, `curry`)

The `unionWith` function in Lodash is specifically designed to merge two arrays and remove duplicates based on a provided equality function.

**Special JS feature or syntax:**

There are no special JavaScript features or syntaxes mentioned in the benchmark.

Related benchmarks:

lodash unionWith vs Set for merging without duplicates test 2 (version: 0)

Comparing performance of: Set&map vs unionWith2

Created: 3 years ago by: Guest

Jump to the latest result

Set&map

unionWith2

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):