Benchmark: Object in vs Object[]

Script Preparation code:

  var object = {},
      array = [],
      i, test = 1000;
  
  for (i = 0; i < 1000; i++) {
   object['something' + i] = true;
   array.push('something' + i);
  }

Tests:

Object in
('something' + test) in object
direct
object['something' + test]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object in
direct

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definition and test cases to explain what's being tested, compared, and their pros and cons.

**Benchmark Definition:**

The benchmark is testing the performance of two approaches to access an object property:

1. **"Object in"`: This approach uses a loop to iterate over an array, and for each iteration, it accesses the object using bracket notation (`object['something' + i]`).
2. **"direct"`: This approach directly accesses the object property using bracket notation (`object['something' + test]`).

**Script Preparation Code:**

The script preparation code creates two variables:

* `object`: an empty object
* `array`: an empty array
* `i`: a loop counter variable initialized to 0
* `test`: a constant set to 1000

A loop is then executed 1000 times, where in each iteration:

* A property on the `object` is created using bracket notation (`object['something' + i] = true`)
* A corresponding element is added to the `array` using push method (`array.push('something' + i)`)

**Html Preparation Code:**

There is no HTML preparation code provided.

**Individual Test Cases:**

The benchmark has two test cases:

1. **"Object in"`**: This test case runs the script preparation code and then executes a loop 1000 times, using the `object['something' + i]` approach to access properties on the object.
2. **"direct"`**: This test case runs the script preparation code and then executes a loop 1000 times, using the `object['something' + test]` approach to access properties on the object.

**Library Usage:**

There is no library usage mentioned in the benchmark definition.

**Special JS Feature/Syntax:**

The benchmark uses bracket notation (`[]`) for property access, which is a common JavaScript feature. No special syntax or features are highlighted in this benchmark.

**Benchmark Results:**

The latest benchmark results show that the `direct` approach (accessing properties using bracket notation without iteration) outperforms the `Object in` approach (iterating over an array and accessing properties on the object).

**Pros and Cons of Each Approach:**

1. **"Object in"`:
	* Pros:
		+ Easy to understand and implement
		+ Allows for more control over iterations
	* Cons:
		+ May lead to slower performance due to iteration overhead
2. **"direct"`:
	* Pros:
		+ Can be faster, especially when accessing properties without iteration
	* Cons:
		+ May require additional effort to handle edge cases and errors

**Other Alternatives:**

If you want to explore alternative approaches, consider the following:

1. Using `Array.prototype.forEach` or `for...of` loop with iterator objects for iteration.
2. Utilizing built-in functions like `Object.keys()` or `Object.values()` to access object properties.
3. Implementing a custom indexing mechanism using JavaScript's `Map` data structure.

Keep in mind that the best approach will depend on your specific use case, performance requirements, and personal preference.

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36

Browser/OS: Chrome 96 on Windows

View result in a separate tab

Test name	Executions per second
Object in	2120324.2 Ops/sec
direct	2266397.5 Ops/sec

Related benchmarks:

Object in vs Object[] (version: 0)

Comparing performance of: Object in vs direct

Created: 5 years ago by: Registered User

Jump to the latest result

Object in

direct

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):