Benchmark: Delete vs destructure for objects without mutating and 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 - mutating
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 - mutating

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**Benchmark Definition**

The provided benchmark, titled "Delete vs destructure for objects without mutating and mutating," aims to compare the performance of different approaches to delete or remove properties from an object in JavaScript.

**Options Compared**

There are four main options being compared:

1. **delete obj.a**: This method uses the built-in `delete` operator to remove a property from an object.
2. **{ a, ...rest } = obj;**: This approach uses destructuring assignment to create a new object with only the desired properties and discards the rest.
3. **const copy = { ...obj }; delete obj.a;**: This method creates a copy of the original object using the spread operator (`{ ...obj }`) and then removes the property from the copy.
4. **const copy = JSON.parse(JSON.stringify(obj)); delete obj.a;**: This approach uses `JSON.stringify` to create a deep copy of the original object, and then removes the property from the copy.

**Pros and Cons**

Here's a brief summary of each option:

1. **delete obj.a**:
	* Pros: Simple and efficient, as it only requires one operation.
	* Cons: Can lead to unexpected behavior if used with complex objects or array properties.
2. **{ a, ...rest } = obj;**:
	* Pros: Creates a new object without mutating the original, making it safer for use in certain scenarios.
	* Cons: May be slower due to the need to create a new object.
3. **const copy = { ...obj }; delete obj.a;**:
	* Pros: Combines the benefits of creating a copy and removing the property, making it more flexible than `delete` alone.
	* Cons: Requires two operations (copy creation and deletion), which may be slower.
4. **const copy = JSON.parse(JSON.stringify(obj)); delete obj.a;**:
	* Pros: Creates a deep copy of the object, ensuring that any nested objects or arrays are also copied.
	* Cons: Uses `JSON.stringify`, which can be slower than other methods and may not work as expected with certain types of data.

**Library and Special JS Features**

In this benchmark, no specific libraries are used. However, the use of `JSON.parse` and `JSON.stringify` implies that the test is aware of the differences in how these functions handle object equality and copying.

There are no special JavaScript features explicitly mentioned or utilized in this benchmark.

**Other Considerations**

When working with objects in JavaScript, it's essential to consider the following:

* Use of `const` and `let` declarations to ensure immutability.
* Avoiding direct modification of objects whenever possible.
* Using libraries like Lodash for utility functions that can improve performance or make code more readable.

For alternative approaches to delete or remove properties from an object, you may want to consider using:

* `Object.keys(obj).indexOf('property_name') >= 0 ? delete obj[property_name] : null;` (iterative approach)
* `Object.defineProperty(obj, 'property_name', { value: undefined });` (using property descriptors)

Keep in mind that these alternatives might not be as efficient or concise as the options tested in this benchmark.

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0

Browser/OS: Firefox 115 on Linux

View result in a separate tab

Test name	Executions per second
delete - assign	10903484.0 Ops/sec
Rest object	12378595.0 Ops/sec
delete - spread operator	11428812.0 Ops/sec
delete - JSON.stringify	2331167.0 Ops/sec
delete - mutating	35662640.0 Ops/sec

Related benchmarks:

Delete vs destructure for objects without mutating and 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 - mutating

Created: one year ago by: Guest

Jump to the latest result

delete - assign

Rest object

delete - spread operator

delete - JSON.stringify

delete - mutating

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):