Benchmark: for-in vs object.keys345345

Script Preparation code:

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); } }
Object.keys
for (var i=10000; i > 0; i--) { for (var key of Object.keys(obj)) { 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:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition and Purpose**

The benchmark is designed to compare the performance of two approaches for iterating over an object: `for-in` loop and `Object.keys()` method.

**Options Compared**

Two options are compared:

1. **For-in Loop**: This approach uses a traditional `for-in` loop, which iterates over the keys of an object using the `in` keyword.
2. **Object.keys() Method**: This approach uses the `Object.keys()` method to get an array of the object's keys, and then iterates over it using a `for...of` loop.

**Pros and Cons**

**For-in Loop:**

Pros:

* Simpler and more familiar syntax for many developers.
* Can be faster in certain cases due to its native implementation.

Cons:

* Less flexible and less predictable than the `Object.keys()` method, as the order of iteration is not guaranteed.
* Can lead to unexpected behavior if the object's properties are added or removed dynamically.

**Object.keys() Method:**

Pros:

* More flexible and predictable than the `for-in` loop, as it always iterates over the keys in a specific order (ascending alphabetical order).
* Less prone to unexpected behavior due to dynamic property changes.
* Can be more efficient for large datasets, as it avoids the overhead of the `in` keyword.

Cons:

* More complex syntax and less familiar to some developers.
* May incur a slight performance overhead due to its native implementation.

**Library Usage**

The benchmark uses the built-in JavaScript functions `Object.keys()` and `for...of` loop.

No external libraries are required for this benchmark, making it easy to run and understand.

**Special JS Features or Syntax**

Neither of the benchmark's test cases utilizes any special JavaScript features or syntax beyond what is considered standard in modern JavaScript development.

**Other Alternatives**

If you're interested in exploring alternative approaches, here are a few options:

* **Array.prototype.forEach()**: Instead of using `for-in` or `Object.keys()` for iteration, you can use the `forEach()` method on an array of keys.
* **Symbol.iterator**: Some objects support the Symbol.iterator property, which allows you to iterate over its properties using a custom iterator function.
* **Custom iterators**: You can also write your own custom iterators using the `Iterator` and `Iterable` prototypes.

Keep in mind that each alternative has its own trade-offs and performance characteristics, so it's essential to consider the specific requirements of your use case when choosing an iteration approach.

Related benchmarks:

for-in vs object.keys345345 (version: 0)

Comparing performance of: for-in vs Object.keys

Created: 3 years ago by: Guest

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):