Benchmark: for-in vs object.keys window assignment

Script Preparation code:

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

Tests:

for-in
window.q1 = 0 for (var i=10000; i > 0; i--) { for (var key in obj) { window.q1 + key; } }
Object.keys
window.q2 = 0 for (var i=10000; i > 0; i--) { Object.keys(obj).forEach(key => window.q2 += 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):

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

**Benchmark Definition**

The benchmark definition is used to create a specific test case. In this case, it defines two different approaches:

1. `for-in`: This approach uses a traditional `for...in` loop to iterate over the object properties.
2. `Object.keys`: This approach uses the `Object.keys()` method to get an array of the object's property names and then iterates over that array.

**Options Compared**

The benchmark is comparing two options:

1. Using a traditional `for...in` loop (`window.q1 = 0 for (var i=10000; i > 0; i--) { ... }`)
2. Using the `Object.keys()` method with `forEach()` to iterate over the object's property names (`window.q2 = 0 Object.keys(obj).forEach(key => window.q2 += key);`)

**Pros and Cons of Each Approach**

**For-in Loop:**

Pros:

* Easy to understand and implement for many developers.
* Can be more efficient for small to medium-sized objects.

Cons:

* Not as modern or JavaScript-standard-compliant as other approaches.
* May not work well with modern object iteration methods or array-like objects.

**Object.keys() Method:**

Pros:

* Modern, JavaScript-standard-compliant, and widely supported.
* Efficiently handles large arrays of property names.
* Can be more memory-efficient than the `for-in` loop for large objects.

Cons:

* May require additional setup or polyfills for older browsers.
* Can be slower for very small objects due to the overhead of creating an array.

**Library Usage**

The test case uses the `Object.keys()` method, which is a built-in JavaScript method. It's used in modern browsers and Node.js environments.

No special JavaScript features or syntax are required for this benchmark.

**Other Considerations**

When writing benchmarks like this one, it's essential to consider factors such as:

* Object size: The test case uses an object with 11 properties. A larger object might favor the `Object.keys()` method due to its efficiency.
* Browser and environment support: Older browsers or environments might not support the `Object.keys()` method, which could skew results.
* Memory usage: Large objects can lead to higher memory usage, affecting performance.

**Alternatives**

Other approaches for iterating over an object's properties include:

1. `for...in`: Traditional loop using the `for...in` construct.
2. Array iteration with `forEach()`: Iterating over an array of property names using `forEach()`.
3. Using a custom iterator: Creating a custom iterator to iterate over the object's properties.

Keep in mind that these alternatives might have different trade-offs and performance characteristics compared to the `Object.keys()` method.

The benchmark can be further optimized or modified by:

* Adjusting the object size to better represent real-world scenarios.
* Including more browsers, environments, or device platforms to improve overall relevance.
* Using a more robust timing mechanism to account for factors like CPU spikes or garbage collection.

Related benchmarks:

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

Comparing performance of: for-in vs Object.keys

Created: 6 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):