Benchmark: Testing speed with Reflect.deleteProperty and delete

Script Preparation code:

var numbers = Array(10).fill(null).map((x, i) => ({[i]: `${i}- ${i}`, [i+1]: i+1 }));

Tests:

Reflect.deleteProperty
numbers.forEach((number, index)=> Reflect.deleteProperty(number, index))
object delete
numbers.forEach((number, index)=> delete number[index])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Reflect.deleteProperty
object delete

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Browser/OS: Chrome 135 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Reflect.deleteProperty	4654816.5 Ops/sec
object delete	5508000.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark and its different approaches.

**Benchmark Overview**

The test measures the performance of two JavaScript methods: `Reflect.deleteProperty` and the built-in `delete` operator, both used to delete properties from an object.

**Script Preparation Code**

The script preparation code creates a large array `numbers` with 10 elements, each containing two properties: `[i]: `${i}- ${i}`, [i+1]: i+1`. This creates a dense object with many key-value pairs.

**Test Cases**

There are two test cases:

1. **Reflect.deleteProperty**: This test case uses the `Reflect.deleteProperty` method to delete the first property of each object in the array. The benchmark definition is: `numbers.forEach((number, index)=> Reflect.deleteProperty(number, index))`.
2. **object delete**: This test case uses the built-in `delete` operator to delete the first property of each object in the array. The benchmark definition is: `numbers.forEach((number, index)=> delete number[index])`.

**Options Compared**

The two approaches differ in their performance:

* **Reflect.deleteProperty**: This method is more efficient than the `delete` operator because it uses a native JavaScript API that's optimized for speed. It also avoids the overhead of property lookup and comparison.
* **object delete**: The `delete` operator, on the other hand, requires the engine to perform additional steps: looking up the property, comparing its value with the current value, and updating the object's internal hash table.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Reflect.deleteProperty**:
	+ Pros:
		- Faster execution speed
		- More efficient than `delete` operator
		- Avoids property lookup and comparison overhead
	+ Cons: None notable
* **object delete**:
	+ Pros:
		- Widespread support across browsers and engines
		- Familiar API for many developers
	+ Cons:
		- Slower execution speed compared to `Reflect.deleteProperty`
		- More overhead due to property lookup and comparison

**Library or Framework**

There is no specific library used in this benchmark. The `Reflect` object is a built-in JavaScript API.

**Special JS Feature or Syntax**

The test uses the `forEach` method, which is a standard JavaScript feature introduced in ECMAScript 5 (ES5). It's a widely supported and familiar API for many developers.

**Other Alternatives**

If you're looking for alternatives to `Reflect.deleteProperty`, you could consider:

* Using a library like Lodash or Underscore.js, which provide similar functionality.
* Implementing your own property deletion logic using a simple loop or recursion.
* Exploring other native JavaScript APIs, such as `Object.keys()` and `Object.prototype.hasOwnProperty.call()`, although these may be less efficient than `Reflect.deleteProperty`.

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

Related benchmarks:

Testing speed with Reflect.deleteProperty and delete (version: 0)

Comparing performance of: Reflect.deleteProperty vs object delete

Created: 2 years ago by: Guest

Jump to the latest result

Reflect.deleteProperty

object delete

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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