Benchmark: Unshift vs Union

HTML Preparation code:

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

Script Preparation code:

function getRandomInt(max) {
  return Math.floor(Math.random() * Math.floor(max));
}

var arr = [];
for(var i = 0; i < 100000; i++){
  arr.push({value:getRandomInt(100)});
}

Tests:

unshift
arr.unshift(51, 345)
_.union
_.union(arr, [51, 345])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
unshift
_.union

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'll break down the benchmark for you.

**Benchmark Overview**

The benchmark compares two approaches:

1. `unshift`: a JavaScript method that adds elements to the end of an array.
2. `_union`: a function from the Lodash library, which merges two arrays into a new array with no duplicates.

**Options Compared**

* **`unshift`**: inserts elements at the beginning of the array.
	+ Pros: can be faster for large arrays since it avoids shifting elements to make room for the new element.
	+ Cons: requires more overhead due to the insertion process, which might lead to slower performance in some cases.
* **`.union()` from Lodash**: merges two arrays into a new array with no duplicates.
	+ Pros: generally faster and more efficient than `unshift`, especially for large arrays or when dealing with duplicate elements.
	+ Cons: requires an additional library (Lodash) and can be slower if the input arrays are very small.

**Considerations**

* The benchmark size is 100,000 elements, which suggests that both approaches should have similar performance characteristics. However, `unshift` might still incur more overhead due to its insertion process.
* The use of Lodash's `.union()` function implies that it provides a way to merge arrays without duplicates in an efficient manner.
* The benchmark doesn't consider other array methods like `concat()`, `push()`, or `splice()`, which could also be used for comparison.

**Library and Syntax**

The benchmark uses the Lodash library, specifically its `.union()` function. This suggests that the author wanted to evaluate the performance of this specific library function in the context of array merging.

There are no special JavaScript features or syntax mentioned in the benchmark. It's a straightforward example of comparing two array manipulation approaches.

**Other Alternatives**

If you were to write this benchmark from scratch, you might consider other alternatives for comparison:

* Using `concat()` instead of `unshift`:
```javascript
arr = arr.concat([51, 345]);
```
* Using `push()` and `splice()` instead of `unshift`:
```javascript
for (var i = 0; i < 100000; i++) {
  arr.push({ value: getRandomInt(100) });
}
arr.splice(0, 0, 51, 345);
```
* Using a different library or implementation for array merging, such as `Array.prototype.reduce()`:
```javascript
arr = arr.reduce((acc, current) => [...acc, ...current], [51, 345]);
```

Keep in mind that these alternatives would change the benchmark's setup and results.

Related benchmarks:

Unshift vs Union (version: 0)

Comparing performance of: unshift vs _.union

Created: 5 years ago by: Guest

Jump to the latest result

unshift

_.union

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):