Benchmark: Test lodash unionBy

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

var source = [{
    id: 48
}, {
    id: 53
}];
var target = [{
    id: 48
}, {
    id: 11
}];

Tests:

differenceBy
const missingID = _(source).differenceBy(target, 'id').valueOf(); const result = target.concat(missingID);
unionBy
const result = _(target).unionBy(source, 'id').valueOf();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
differenceBy
unionBy

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided benchmark definition and test cases.

**Benchmark Definition:**

MeasureThat.net is measuring the performance of two JavaScript functions, `unionBy` and `differenceBy`, which are part of the Lodash library. The two functions operate on arrays and perform set operations (union and difference).

**Lodash Library:**

Lodash is a popular JavaScript utility library that provides a collection of helper functions for tasks such as array manipulation, object manipulation, functional programming, and more.

In this case, `differenceBy` takes two arrays and an optional callback function, and returns a new array containing elements from the first array that do not have matching values in the second array based on the provided key (in this case, `'id'`). The returned array contains only unique values from the source array.

On the other hand, `unionBy` takes two arrays and an optional callback function, and returns a new array containing elements from both arrays that have unique values when compared using the provided key (in this case, `'id'`).

**Options Compared:**

The benchmark is comparing two approaches:

1. **Concatenation (`concat`)**: The `differenceBy` function uses concatenation to merge the result with the target array.
2. **Set Operations (`unionBy`)**: The `unionBy` function uses set operations (union) to merge the results.

**Pros and Cons:**

1. **Concatenation (`concat`)**:
	* Pros:
		+ Easy to understand and implement
		+ No additional dependencies required
	* Cons:
		+ Creates a new array with duplicate values, leading to increased memory usage and potentially slower performance
		+ Can be less efficient than set operations for large datasets
2. **Set Operations (`unionBy`)**:
	* Pros:
		+ More efficient than concatenation for large datasets
		+ Reduces memory usage by avoiding duplicates
	* Cons:
		+ May require more complex understanding of the underlying data structures and algorithms
		+ Might be less intuitive to implement

**Special JS Features/Syntax:**

In this benchmark, JavaScript's `_( )` syntax is used as a shorthand for creating an Lodash object. This syntax is specific to the Lodash library and allows users to create functions like `differenceBy` and `unionBy` with minimal code.

**Other Considerations:**

1. **Cache Control**: MeasureThat.net uses a caching mechanism to store benchmark results, which can affect the accuracy of the test.
2. **Device and Browser Variability**: The benchmark measures performance across different devices (Desktop) and browsers (Chrome 91), which helps ensure the results are representative of real-world use cases.

**Alternative Approaches:**

For set operations in JavaScript, other alternatives to `unionBy` include:

1. Using `Set` objects directly (e.g., `new Set()`).
2. Utilizing libraries like [Underscore.js](https://github.com/jashkenaz/underscore) or [FastSet](https://fastset.io/) that provide set operations.

Keep in mind that these alternatives may have varying levels of complexity and performance characteristics compared to Lodash's `unionBy` function.

Related benchmarks:

Test lodash unionBy (version: 0)

unionBy vs concat

Comparing performance of: differenceBy vs unionBy

Created: 5 years ago by: Guest

Jump to the latest result

differenceBy

unionBy

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):