Benchmark: Lodash uniqBy vs Set vs Set spread

HTML Preparation code:

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

Script Preparation code:

var MyArr = Array.from({length: 40}, () => Math.floor(Math.random() * 40));

var myCopy = null;

Tests:

Lodash uniqBy
myCopy = _.uniqBy(MyArr);
Set
myCopy = new Set(MyArr)
Set spread
myCopy = [...(new Set(MyArr))]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Lodash uniqBy
Set
Set spread

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36

Browser/OS: Chrome 133 on Windows

View result in a separate tab

Test name	Executions per second
Lodash uniqBy	2780621.8 Ops/sec
Set	2626933.0 Ops/sec
Set spread	2447516.5 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's dive into the explanation.

**Overview**

The provided JSON represents a JavaScript microbenchmark test case on MeasureThat.net. The benchmark tests three approaches to removing duplicate elements from an array: using Lodash's `uniqBy` function, creating a new `Set` object, and spreading the `Set` object using the spread operator (`[...]`).

**Tested Approaches**

1. **Lodash uniqBy**: This approach uses the Lodash library's `uniqBy` function to remove duplicate elements from the array based on a custom comparison function.
2. **Set**: This approach creates a new `Set` object and adds each element of the original array to it. Since sets only store unique values, this approach removes duplicates automatically.
3. **Set spread**: This approach creates a new `Set` object and spreads its elements into an array using the spread operator (`[...]`). The resulting array will have duplicate elements removed.

**Pros and Cons**

1. **Lodash uniqBy**:
	* Pros: Customizable comparison function allows for fine-grained control over duplicate removal.
	* Cons: Requires Lodash library to be included, which may add unnecessary overhead.
2. **Set**:
	* Pros: Fast and efficient, as sets only store unique values.
	* Cons: Does not preserve the original array order, and may require additional processing to restore it.
3. **Set spread**:
	* Pros: Preserves the original array order and is relatively fast.
	* Cons: May be slower than using a `Set` object directly, as it involves creating an intermediate array.

**Library: Lodash**

Lodash (a library of functions for functional JavaScript programming) provides the `uniqBy` function, which removes duplicate elements from an array based on a custom comparison function. The comparison function is used to determine whether two elements are equal or not.

**Special JS Feature/Syntax: Spread Operator ([...] )**

The spread operator is used in the "Set spread" approach to create a new array by spreading the elements of the `Set` object. This syntax was introduced in ECMAScript 2015 (ES6) and allows for easy creation of arrays from other iterables, such as sets.

**Other Alternatives**

1. **Array.prototype.filter()**: Instead of using a `Set` object or Lodash's `uniqBy` function, you could use the `filter()` method to remove duplicate elements from an array.
2. **Object.values() and Array.from()**: If you need to preserve the original array order, you could use `Object.values()` to get the values of an object (which can be used as a set), followed by `Array.from()` to create an array from it.

Here's some sample code using these alternatives:

```javascript
// Using filter()
var myArr = [...]; // your array
var myCopy = myArr.filter((val, index, self) => {
  return index === self.indexOf(val);
});

// Using Object.values() and Array.from()
var obj = { /* your object */ };
var myObjSet = new Set(Object.values(obj));
var myCopySpread = [...myObjSet];
```

Related benchmarks:

Lodash uniqBy vs Set vs Set spread (version: 0)

Comparing performance of: Lodash uniqBy vs Set vs Set spread

Created: 2 years ago by: Guest

Jump to the latest result

Lodash uniqBy

Set

Set spread

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):