Benchmark: for-in vs object.keys

Script Preparation code:

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

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

Tests:

for-in

for (var i=10000; i > 0; i--) {
  for (var key in obj) {
      console.log(key); 
  }
}

 
for (var i=10000; i > 0; i--) {  for (var key in obj) {      console.log(key);   }}

Object.keys
for (var i=10000; i > 0; i--) { Object.keys(obj).forEach(key => console.log(key)); }
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

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
for-in
Object.keys

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 hours ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36

Browser/OS: Chrome 134 on Windows

View result in a separate tab

Test name	Executions per second
for-in	4.4 Ops/sec
Object.keys	4.3 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 5 months ago):

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

Benchmark Definition

The benchmark definition is provided in JSON format, which represents two test cases: for-in and Object.keys. The script preparation code is the same for both test cases, which defines an object obj with 7 properties. This object will be used as the input for both tests.

Options Compared

The two test cases compare the performance of two approaches to iterate over the properties of the object:

For-in loop: The first test case uses a traditional for-in loop, which iterates over the object's properties using the in keyword.
Object.keys() method: The second test case uses the Object.keys() method, which returns an array of the object's property names.

Pros and Cons

For-in loop:
- Pros: Can be more flexible when working with objects that have custom properties or methods.
- Cons: Can be slower due to the overhead of iterating over the object's properties using in.
Object.keys() method:
- Pros: Fast and efficient, as it uses an internal optimized algorithm to retrieve property names.
- Cons: May not work correctly with objects that have custom properties or methods.

In general, Object.keys() is a faster approach, but it may not be suitable for all use cases. The choice between the two ultimately depends on the specific requirements of your application.

Library Used

There is no explicit library mentioned in the benchmark definition. However, both test cases rely on JavaScript's built-in object and array methods (Object.keys()).

Special JS Feature/Syntax

Neither test case uses any special JavaScript features or syntax beyond what is required to demonstrate the comparison between the two approaches.

Other Alternatives

If you wanted to add more alternatives to this benchmark, some options could include:

Using for...of loop instead of for-in loop.
Using Array.prototype.forEach() method with an array of property names instead of Object.keys().
Using a third-party library like Lodash or Underscore.js for iterating over object properties.

By adding more alternatives, you could provide a more comprehensive comparison and give users more options to explore.

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition**

The benchmark definition is provided in JSON format, which represents two test cases: `for-in` and `Object.keys`. The script preparation code is the same for both test cases, which defines an object `obj` with 7 properties. This object will be used as the input for both tests.

**Options Compared**

The two test cases compare the performance of two approaches to iterate over the properties of the object:

1. **For-in loop**: The first test case uses a traditional `for-in` loop, which iterates over the object's properties using the `in` keyword.
2. **Object.keys() method**: The second test case uses the `Object.keys()` method, which returns an array of the object's property names.

**Pros and Cons**

* **For-in loop**:
	+ Pros: Can be more flexible when working with objects that have custom properties or methods.
	+ Cons: Can be slower due to the overhead of iterating over the object's properties using `in`.
* **Object.keys() method**:
	+ Pros: Fast and efficient, as it uses an internal optimized algorithm to retrieve property names.
	+ Cons: May not work correctly with objects that have custom properties or methods.

In general, `Object.keys()` is a faster approach, but it may not be suitable for all use cases. The choice between the two ultimately depends on the specific requirements of your application.

**Library Used**

There is no explicit library mentioned in the benchmark definition. However, both test cases rely on JavaScript's built-in object and array methods (`Object.keys()`).

**Special JS Feature/Syntax**

Neither test case uses any special JavaScript features or syntax beyond what is required to demonstrate the comparison between the two approaches.

**Other Alternatives**

If you wanted to add more alternatives to this benchmark, some options could include:

1. Using `for...of` loop instead of `for-in` loop.
2. Using `Array.prototype.forEach()` method with an array of property names instead of `Object.keys()`.
3. Using a third-party library like Lodash or Underscore.js for iterating over object properties.

By adding more alternatives, you could provide a more comprehensive comparison and give users more options to explore.

Related benchmarks:

for-in vs object.keys (version: 0)

Comparing performance of: for-in vs Object.keys

Created: 7 years ago by: Guest

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