Benchmark: Delete vs destructure for objects in loop

Script Preparation code:

var obj = {}
for (let i = 0; i < 1000; i++) {
	obj[`test_${i}`] = `value_${i}`;
}

Tests:

delete
const newObject = { ...obj }; Object.keys(newObject).forEach(key => { delete newObject[key]; });
Rest object
let newObject = obj; Object.keys(newObject).forEach(property => { let {[property]:ignored, ...rest} = newObject newObject = rest; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
delete
Rest object

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36

Browser/OS: Chrome 133 on Linux

View result in a separate tab

Test name	Executions per second
delete	3492.3 Ops/sec
Rest object	15.9 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and some considerations.

**Benchmark Purpose**

The primary goal of this benchmark is to measure the performance difference between two approaches:

1. Deleting properties from an object using `delete`.
2. Removing properties from an object by destructuring it into a new object with only the desired properties (`...rest`).

**Options Compared**

Two options are being compared:

* **Delete**: Using the `delete` operator to remove properties from the object.
* **Rest object**: Destructuring the object and creating a new one with only the desired properties.

**Pros and Cons of Each Approach:**

1. **Delete**:
	* Pros:
		+ Easy to understand and implement.
		+ Works for any property, regardless of its name or value.
	* Cons:
		+ Can be slower due to the overhead of calling `delete` on each property.
		+ May cause issues with property names that are reserved keywords in JavaScript (e.g., `break`, `case`, etc.).
2. **Rest object**:
	* Pros:
		+ Typically faster than using `delete`.
		+ Avoids potential issues with reserved keywords.
	* Cons:
		+ Requires a good understanding of destructuring syntax and can be more error-prone if not implemented correctly.

**Library or Special JS Feature Used:**

Neither option uses any external libraries, but they do rely on JavaScript's built-in features:

1. **Delete**: The `delete` operator is a native JavaScript function.
2. **Rest object**: Destructuring syntax (`...rest`) is a feature introduced in ECMAScript 2015 (ES6).

**Other Considerations:**

* The benchmark uses a simple object creation and property assignment pattern to warm up the interpreter before running each test.
* Both tests have similar execution patterns, with the `delete` option deleting all properties from the object, while the `Rest object` option only removes the desired properties.

**Alternatives:**

Other approaches to removing properties from an object could include:

1. Using a library like Lodash's `omit()` function.
2. Creating a new object with only the desired properties using the spread operator (`{ ...newObject }`).
3. Using a different data structure, such as an array or a Map, if possible.

However, these alternatives may not be relevant to this specific benchmark, which focuses on comparing the performance of `delete` versus destructuring syntax.

Related benchmarks:

Delete vs destructure for objects in loop (version: 0)

Measure the performance of delete versus removing a prop from an object in loop

Comparing performance of: delete vs Rest object

Created: 4 years ago by: Registered User

Jump to the latest result

delete

Rest object

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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