Benchmark: _.forIn vs for in

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(i=0; i<10000; i++){
  var number = (i + 1);
  obj['key-' + number] = number
}

Tests:

_.forIn
var array1 = []; _.forIn(obj, function (val, key) { array1.push(val) });
for in
var array2 = []; var key; for (key in obj) { if (obj.hasOwnProperty(key)) { array2.push(obj[key]) } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
_.forIn
for in

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its options.

**Benchmark Overview**

The benchmark compares two JavaScript iteration approaches: `_.forIn` from Lodash library and traditional `for...in`. The test creates an object with 10,000 properties (keys) and iterates over it using both methods, pushing values to an array for comparison.

**Options Compared**

1. **_.forIn**: This is a function from the Lodash library that iterates over objects using a custom callback function (`val` and `key` parameters). It's designed to work with objects in a more functional programming style.
2. **Traditional `for...in`**: A built-in JavaScript loop that iterates over object properties, including inherited ones.

**Pros and Cons**

### _.forIn

Pros:

* More efficient: Lodash's implementation is optimized for performance.
* Less verbose: The callback function reduces boilerplate code.
* Works with any iterable (not limited to objects).

Cons:

* External dependency: Requires the Lodash library.
* Not part of standard JavaScript: May not be supported by older browsers or environments.

### Traditional `for...in`

Pros:

* No external dependencies needed.
* Part of standard JavaScript, making it more widely compatible.
* Easy to understand and implement.

Cons:

* More verbose due to the need for a separate check (`obj.hasOwnProperty(key)`).
* Inefficient: Iterates over inherited properties, which may not be desirable in all cases.

**Library**

In this benchmark, Lodash is used as the library. Its primary purpose is to provide utility functions for functional programming and object manipulation. In this specific case, `_.forIn` is used to simplify the iteration process.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax mentioned in this benchmark. It only uses standard JavaScript constructs.

**Alternatives**

If you wanted to implement a similar benchmark using only standard JavaScript, you could use a traditional `for...in` loop without checking for inherited properties:
```javascript
var array = [];
for (var key in obj) {
  if (obj.hasOwnProperty(key)) {
    array.push(obj[key]);
  }
}
```
However, this approach is less efficient and more verbose than the Lodash implementation.

Keep in mind that this benchmark focuses on comparing two specific iteration approaches rather than exploring other optimization techniques or edge cases.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.114 Safari/537.36

Browser/OS: Chrome 89 on Windows

View result in a separate tab

Test name	Executions per second
_.forIn	566.6 Ops/sec
for in	233.4 Ops/sec

Related benchmarks:

_.forIn vs for in (version: 0)

Comparing performance of: _.forIn vs for in

Created: 3 years ago by: Guest

Jump to the latest result

_.forIn

for in

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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