Benchmark: reduce-vs-uniqBy_2

HTML Preparation code:

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

Script Preparation code:

var workOrders = _.range(_.random(1000)).map(x => ({
  assigneeId: Math.random().toString(36).slice(3),
  assigneName: 'LordWarlock'
}));

Tests:

Array.prototype.reduce()
workOrders.reduce((accumulator, workOrder) => { if (!workOrder.assigneeId) { return accumulator; } const assigneeExists = accumulator.find(assignee => assignee.assigneeId === workOrder.assigneeId); if (!assigneeExists) { accumulator.push(workOrder) } return accumulator; }, []);
_.uniqBy
_.uniqBy(workOrders, 'assigneeId');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.reduce()
_.uniqBy

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.157 Safari/537.36

Browser/OS: Chrome 74 on Mac OS X 10.14.4

View result in a separate tab

Test name	Executions per second
Array.prototype.reduce()	382.9 Ops/sec
_.uniqBy	8471.3 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks and explore what's being tested in this specific benchmark.

**Overview**

The benchmark compares two approaches to extract unique items from an array: using `Array.prototype.reduce()` versus using the `_` library's `uniqBy()` function. The goal is to determine which approach is faster.

**Options compared**

There are only two options being compared:

1. **`Array.prototype.reduce()`**: This method applies a callback function to each element in the array, accumulating a value that is returned as the final result.
2. **`.uniqBy()` from the `_` library**: This function takes an array and a property path (in this case, `'assigneeId'`) and returns a new array with unique values.

**Pros and Cons**

* **`Array.prototype.reduce()`**:
	+ Pros: widely supported, no dependencies.
	+ Cons: can be slower due to the overhead of callback functions, potentially less efficient for large datasets.
* **`.uniqBy()` from the `_` library**:
	+ Pros: optimized for performance, handles edge cases like null or undefined values, and is often faster than `Array.prototype.reduce()`.
	+ Cons: requires additional dependencies (the `_` library), which may impact performance.

**Library: _**

The `_` library is a popular utility library that provides a wide range of functions for common tasks, such as array manipulation, string manipulation, and more. In this benchmark, `.uniqBy()` is used to extract unique items from the `workOrders` array based on the `'assigneeId'` property.

**Special JS feature or syntax: None**

There are no special JavaScript features or syntax being used in this benchmark.

**Other alternatives**

If you want to implement your own solution without using the `_` library, you could use a simple approach like:

```javascript
const uniqueItems = [];
for (const workOrder of workOrders) {
  if (!uniqueItems.find(item => item.assigneeId === workOrder.assigneeId)) {
    uniqueItems.push(workOrder);
  }
}
```

However, this implementation is likely to be slower than using the `.uniqBy()` function or `Array.prototype.reduce()`, especially for large datasets.

**Benchmark preparation code**

The script preparation code generates a random array of objects with duplicate `'assigneeId'` values:
```javascript
var workOrders = _.range(_.random(1000)).map(x => ({ assigneeId: Math.random().toString(36).slice(3), assigneName: 'LordWarlock' }));
```
The HTML preparation code includes the `_` library's minified version.

I hope this explanation helps!

Related benchmarks:

reduce-vs-uniqBy_2 (version: 0)

Compare different ways of extracting unique items

Comparing performance of: Array.prototype.reduce() vs _.uniqBy

Created: 5 years ago by: Guest

Jump to the latest result

Array.prototype.reduce()

_.uniqBy

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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