Benchmark: pickby vs filter on object

HTML Preparation code:

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

Script Preparation code:

var obj = {}
for (let i = 0; i < 1000; i++) {
  obj[String(i)] = Math.floor(Math.random() * 6) + 1
} 
var predicate = v => v % 2 === 0;

Tests:

pickby
_.pickBy(obj, predicate);
filter
Object.keys(obj).filter((e) => predicate(e))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
pickby
filter

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/147.0.0.0 Safari/537.36

Browser/OS: Chrome 147 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
pickby	24177.4 Ops/sec
filter	89163.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested, along with the pros and cons of each approach.

**Benchmark Overview**

The test case compares two approaches for filtering an object: `_.pickBy` from Lodash and `Object.keys().filter()`. Both methods are used to filter an object where the key-value pairs need to be retained only if a condition is met. In this benchmark, the condition is that the value should be odd (`v % 2 !== 0`).

**Lodash _.pickBy**

The Lodash library provides a function called `_.pickBy()` which takes two arguments: an object and a predicate function. The predicate function is applied to each key in the object, and if it returns `true`, the corresponding value is included in the resulting object.

Pros:

* More concise and expressive way of filtering objects
* Often faster than vanilla JavaScript approaches due to Lodash's optimized implementation

Cons:

* Requires including an external library (in this case, Lodash)
* May not be as well-known or understood by developers without a strong background in functional programming or Lodash

**Vanilla JavaScript Object.keys().filter()**

The `Object.keys()` method returns an array of the object's keys, which can then be filtered using the `Array.prototype.filter()` method.

Pros:

* No external libraries are required
* Widely supported and understood by developers
* Can be useful for learning or demonstrating basic JavaScript concepts

Cons:

* Often slower than Lodash-based approaches due to the overhead of creating an array and filtering it
* More verbose code can lead to readability issues

**Other Considerations**

When comparing these two approaches, consider the following factors:

* Readability: How easy is it to understand the intent behind each approach? Which one requires more boilerplate code or is more concise?
* Maintainability: Which approach is easier to maintain and update if the filtering logic changes?
* Performance: In what scenarios will one approach outperform the other?

**Library Explanation**

In this benchmark, Lodash is used as a library to provide the `_.pickBy()` function. Lodash is a popular JavaScript utility library that provides a wide range of functions for tasks such as string manipulation, array and object manipulation, and more.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax being tested in this benchmark. However, it's worth noting that the `String(i)` function call is used to create keys for the object, which may be less readable than using a simple numeric index. In modern JavaScript, you might prefer to use an array of numbers instead: `[0, 1, ..., 999]`.

**Alternatives**

Other alternatives for filtering objects in JavaScript include:

* Using a custom function with `Object.keys()` and `Array.prototype.filter()`
* Utilizing libraries like Ramda or Lodash's sister project, UglifyJS
* Leveraging modern JavaScript features like arrow functions or destructuring

For this specific benchmark, if you wanted to exclude the external library dependency, you could rewrite the `_.pickBy` test case using a custom function and `Object.keys()`:
```javascript
const obj = {};
for (let i = 0; i < 1000; i++) {
  obj[String(i)] = Math.floor(Math.random() * 6) + 1;
}
function filter(obj, predicate) {
  const keys = Object.keys(obj);
  return keys.filter(key => predicate(parseInt(key)));
}
const result = filter(obj, v => v % 2 !== 0);
```
This implementation uses the `Object.keys()` method to get an array of keys and then filters it using a custom `filter` function.

Related benchmarks:

pickby vs filter on object (version: 0)

Comparing performance of: pickby vs filter

Created: 3 years ago by: Guest

Jump to the latest result

pickby

filter

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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