Benchmark: for-in vs object.keys FOR trebushnoyD

Script Preparation code:

var obj = {
  'a': 'trebushnoyvv',
  'b': 1,
  'c': 'trebushnoyvv',
  'd': 1,
  'e': 'trebushnoyvv',
  'f': 1,
  'g': 'trebushnoyvv'
};

Tests:

for-in
for (var i=10000; i > 0; i--) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { console.log(key); } } }
object.keys
for (var i=10000; i > 0; i--) { Object.keys(obj).forEach(key => console.log(key)); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for-in
object.keys

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.

Let's break down the provided JSON data and explain what's being tested.

**Benchmark Definition**

The `Name` field in the benchmark definition JSON indicates that we're testing two different approaches: using a traditional `for...in` loop versus using the `Object.keys()` method.

**Script Preparation Code**

In this case, the script preparation code is a simple JavaScript object (`obj`) with 7 properties. The object has both string and numeric values, which will likely affect the results of the benchmark.

The `for-in` loop in the first test case iterates over all enumerable properties (including inherited ones) of the `obj` object using `Object.prototype.hasOwnProperty.call()`. This is an older way to iterate over objects, but it can be slow due to the overhead of checking each property's existence.

The second test case uses the `Object.keys()` method to get an array of the object's own enumerable properties. This method returns a new array containing only the own enumerable string-valued property names. It's generally faster and more efficient than using `for...in` for this purpose.

**Html Preparation Code**

There is no HTML preparation code provided, which means that the benchmark tests are focused on JavaScript performance only.

**Individual Test Cases**

We have two individual test cases:

1. **for-in**: This test case uses a traditional `for...in` loop to iterate over the properties of the `obj` object.
2. **object.keys**: This test case uses the `Object.keys()` method to get an array of the object's own enumerable properties.

**Comparison**

The comparison between these two approaches is likely focused on performance, specifically how fast each one can execute the loop for a given dataset (in this case, 10,000 iterations).

**Pros and Cons**

* **for-in**:
	+ Pros: Simple to implement, doesn't require any external libraries.
	+ Cons: Can be slower due to the overhead of checking each property's existence.
* **object.keys**:
	+ Pros: Generally faster and more efficient for iterating over object properties.
	+ Cons: Requires the `Object` namespace, which may introduce some overhead.

Other considerations include:

* The specific JavaScript engine used in the benchmarking process (in this case, Chrome 78).
* The device platform and operating system used to run the benchmarks (desktop Windows).
* Any other potential factors that could affect performance, such as cache effects or other optimization techniques.

**Libraries**

There are no external libraries mentioned in the provided data. However, it's worth noting that `Object.keys()` is a built-in method of the JavaScript `Object` namespace, so it doesn't require any additional libraries to be included.

**Special JS Features/Syntax**

The benchmark uses two special JavaScript features:

* The `for...in` loop with `Object.prototype.hasOwnProperty.call()`, which was used before the introduction of the safer and more efficient `hasOwnProperty()` method.
* The use of a modern JavaScript feature like `forEach()` in combination with `Object.keys()`.

However, since these are standard JavaScript features, no special explanation is required.

Related benchmarks:

for-in vs object.keys FOR trebushnoyD (version: 1)

Comparing performance of: for-in vs object.keys

Created: 4 years ago by: Registered User

Jump to the latest result

for-in

object.keys

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):