Benchmark: Delete vs destructure for objects with and without mutating

Script Preparation code:

var obj = {
  a:1,
  b:2,
  c:3
}

Tests:

delete - assign
const copy = Object.assign({}, obj); delete obj.a
Rest object
const { a, ...rest } = obj;
delete - spread operator
const copy = { ...obj } delete obj.a
delete - JSON.stringify
const copy = JSON.parse(JSON.stringify(obj)); delete obj.a
delete - mutation
delete obj.a

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
delete - assign
Rest object
delete - spread operator
delete - JSON.stringify
delete - mutation

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

Measuring performance in JavaScript can be complex, especially when it comes to different approaches and nuances.

**Benchmark Overview**

The provided benchmark compares the performance of four different ways to delete properties from an object:

1. `delete` operator (direct deletion)
2. Using the spread operator (`{ ...obj }`)
3. Creating a copy using `Object.assign()` and then deleting the property
4. Serializing and deserializing the object using `JSON.parse(JSON.stringify(obj))`

**Comparison**

The comparison is based on the number of executions per second, which indicates how many times each approach can be executed within one second.

Here's a brief analysis of each approach:

1. **delete operator (direct deletion)**: This approach uses the built-in `delete` operator to delete a property from an object. It's simple and straightforward.
	* Pros: Fast, efficient, and widely supported.
	* Cons: May not work in older browsers or environments that don't support this syntax.
2. **Using the spread operator (`{ ...obj }`)**: This approach uses the spread operator to create a new object with all properties from `obj`, except for the one being deleted.
	* Pros: Fast, efficient, and widely supported.
	* Cons: Creates a new object, which can lead to memory allocation issues in some cases.
3. **Creating a copy using `Object.assign()`**: This approach creates a shallow copy of the original object using `Object.assign()`, deletes the property from the copy, and then assigns it back to the original object.
	* Pros: Creates a new object, which can help prevent unexpected side effects, but also introduces memory allocation overhead.
	* Cons: Can be slower than direct deletion due to the creation of an intermediate copy.
4. **Serializing and deserializing using `JSON.parse(JSON.stringify(obj))`**: This approach serializes the entire object using `JSON.parse()` and then deserializes it back to a new object, deletes the property from the new object.
	* Pros: Creates a deep copy of the original object, which can help prevent unexpected side effects.
	* Cons: Slow due to the serialization and deserialization process.

**Library Usage**

The benchmark uses the `Object` class, which is part of the JavaScript standard library. The `Object.assign()` method is also part of the standard library.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax used in this benchmark that would require a deep understanding of the language.

**Other Alternatives**

If you're interested in exploring other approaches, here are some alternatives:

1. **Using `Object.keys()` and `Object.prototype.hasOwnProperty.call()`**: This approach iterates over the object's keys and checks if a specific key exists using `hasOwnProperty()`. While it works, it can be slower than direct deletion.
2. **Using `for...in` loop**: Similar to the previous alternative, this approach uses a `for...in` loop to iterate over the object's properties and delete the desired property. However, it may not work correctly if there are inherited properties.

Keep in mind that these alternatives might have different performance characteristics and trade-offs compared to the original benchmark approaches.

I hope this explanation helps you understand the nuances of JavaScript deletion performance!

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36 Edg/116.0.1938.81

Browser/OS: Chrome 116 on Windows

View result in a separate tab

Test name	Executions per second
delete - assign	1552014.5 Ops/sec
Rest object	1771150.1 Ops/sec
delete - spread operator	1857297.4 Ops/sec
delete - JSON.stringify	1260136.6 Ops/sec
delete - mutation	18860210.0 Ops/sec

Related benchmarks:

Delete vs destructure for objects with and without mutating (version: 0)

Measure the performance of delete versus removing a prop from an object without mutating

Comparing performance of: delete - assign vs Rest object vs delete - spread operator vs delete - JSON.stringify vs delete - mutation

Created: one year ago by: Guest

Jump to the latest result

delete - assign

Rest object

delete - spread operator

delete - JSON.stringify

delete - mutation

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):