Benchmark: for-in vs object.keys - log object

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

**What is being tested?**

The provided benchmark measures the performance difference between two approaches for iterating over an object's properties:

1. **For-in loop**: This method uses a traditional `for` loop with an incrementing variable (`i`) to iterate over the object's properties, accessing each value through the property name (`obj[key]`). The loop logs the value of each property to the console.
2. **Object.keys() method**: This method returns an array-like object containing the names of all properties in the object, which can then be iterated over using a `forEach` callback or other iteration methods.

**Options compared**

The two approaches are compared:

* **For-in loop**: A traditional, explicit loop that increments and checks each property name.
* **Object.keys() method**: A more concise, modern approach that returns an array-like object of property names.

**Pros and Cons**

* **For-in loop**:
	+ Pros: Easy to understand and implement, works well for small objects or specific use cases.
	+ Cons: Can be slower due to the incrementing variable and potential overhead from checking each property name.
* **Object.keys() method**:
	+ Pros: More concise, efficient, and suitable for large datasets. It avoids the overhead of incrementing a variable.
	+ Cons: May require additional setup or handling if not used correctly.

In general, the Object.keys() method is preferred when:

* You have a large dataset or need to iterate over many properties.
* You want a more concise and modern way of iterating over an object's properties.

However, for small objects or specific use cases, the For-in loop might be faster and easier to understand.

**Library used**

None. The benchmark uses built-in JavaScript methods (Object.keys()) without any external libraries.

**Special JS feature or syntax**

The benchmark does not mention any special features or syntax, but it is worth noting that the use of `forEach` with Object.keys() relies on modern JavaScript syntax.

**Other alternatives**

If you wanted to test other approaches, some alternative options could be:

* Using a traditional `for...in` loop with an array of property names (e.g., `obj['a'].length`, etc.)
* Implementing your own iteration logic using `Object.entries()` and a custom loop
* Using a library like Lodash or Ramda for more concise and expressive iteration over objects

Keep in mind that these alternatives might not be as efficient or straightforward to implement as the Object.keys() method.

Related benchmarks:

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

Comparing performance of: for-in vs Object.keys

Created: 4 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):