Benchmark: Object.hasOwnProperty vs Object in vs Object[] vs Array.indexOf vs Array.includes times 10

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.hasOwnProperty
object.hasOwnProperty('something' + test)
Object in
('something' + test) in object
Array.indexOf
array.indexOf('something' + test) !== -1
direct
object['something' + test] === true
Array includes
array.includes('something' + test)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.hasOwnProperty
Object in
Array.indexOf
direct
Array includes

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON benchmark definition and explain what's being tested, the pros and cons of different approaches, and other considerations.

**Benchmark Definition**

The benchmark measures the performance of four different ways to check if a property exists in an object or array:

1. `Object.hasOwnProperty`
2. `Object in`
3. `Array.indexOf` (note: this is not strictly checking for existence, but rather finding the index of the value)
4. `Array.includes`

**Script Preparation Code**

The script preparation code creates two objects and arrays:

* An object (`object`) with 1000 properties, each initialized to `true`.
* An array (`array`) with 1000 elements, each containing a string.

This setup is likely designed to maximize the chances of finding a match when checking for existence.

**Individual Test Cases**

Each test case checks if a specific property exists in the object or array using one of the four methods:

1. `object.hasOwnProperty('something' + test)`
2. `'something' + test` in `object`
3. `array.indexOf('something' + test) !== -1`
4. `array.includes('something' + test)`

**Pros and Cons**

Here's a brief analysis of each approach:

1. **Object.hasOwnProperty**
	* Pros: Simple, straightforward, and widely supported.
	* Cons: Can be slower than other approaches for large objects due to the overhead of property lookup.
2. **Object in**
	* Pros: Similar performance to `hasOwnProperty` for small objects, but may be slower for large ones.
	* Cons: Less readable and less intuitive than `hasOwnProperty`.
3. **Array.indexOf**
	* Pros: Fast and efficient for arrays, as it uses binary search.
	* Cons: Not designed for existence checks; returns the index of the first occurrence or -1 if not found. May be slower than other approaches for small arrays.
4. **Array.includes**
	* Pros: Similar performance to `indexOf` for small arrays, and more readable for existence checks.
	* Cons: Less efficient than `indexOf` for large arrays due to the overhead of string lookup.

**Other Considerations**

* **Cache locality**: The use of a large object with many properties may lead to better cache locality, reducing the number of memory accesses and improving performance.
* **Virtual machine**: JavaScript engines like V8 (used by Chrome) have a virtual machine that can optimize certain operations. This might affect the relative performance of different approaches.
* **Compiler optimizations**: The compiler can also impact performance, as it may optimize away unnecessary branches or loops.

**Library**

The `includes` method uses the `String.prototype.includes` method, which is implemented in JavaScript standards and optimized by most browsers.

**Special JS Feature/Syntax**

There is no specific JavaScript feature or syntax mentioned in this benchmark. However, the use of template literals (e.g., `'something' + test`) is a relatively modern feature introduced in ECMAScript 2015.

**Alternatives**

If you're looking for alternative approaches to check if an object property exists, consider using:

* `Object.keys().includes(key)`: A more modern and readable approach that uses the `keys()` method.
* `Array.prototype.some()`: A more efficient approach that uses a single loop.
* Native methods like `Map.has` or `Set.has`, which are optimized for existence checks.

Keep in mind that these alternatives might have different performance characteristics depending on your specific use case and JavaScript engine.

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_5_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.5 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 17 on iOS 17.5.1

View result in a separate tab

Test name	Executions per second
Object.hasOwnProperty	12656720.0 Ops/sec
Object in	11975800.0 Ops/sec
Array.indexOf	730114.2 Ops/sec
direct	11466132.0 Ops/sec
Array includes	269173.2 Ops/sec

Related benchmarks:

Object.hasOwnProperty vs Object in vs Object[] vs Array.indexOf vs Array.includes times 10 (version: 0)

Comparing performance of: Object.hasOwnProperty vs Object in vs Array.indexOf vs direct vs Array includes

Created: 3 months ago by: Guest

Jump to the latest result

Object.hasOwnProperty

Object in

Array.indexOf

direct

Array includes

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):