Benchmark: Delete vs Rest object

Script Preparation code:

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

Tests:

Delete
delete obj.a
Rest object
const { a, ...rest } = obj;

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: 10 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36

Browser/OS: Chrome 138 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Delete	103251224.0 Ops/sec
Rest object	3864877.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**What is tested?**

The benchmark tests two different approaches to removing or deleting properties from an object in JavaScript:

1. **`delete obj.a`**: This approach uses the `delete` operator to remove a property from the `obj` object.
2. **`const { a, ...rest } = obj;`**: This approach uses destructuring assignment to extract the desired property (`a`) and a new object containing all other properties (`rest`) from the original object.

**Options compared**

The benchmark compares these two approaches to see which one is faster in terms of execution time.

**Pros and Cons of each approach:**

1. **`delete obj.a`**:
	* Pros:
		+ Simple and concise syntax.
		+ Works with most JavaScript engines, including older ones like V8 6.x.
	* Cons:
		+ May not be as efficient as the destructuring assignment method for large objects.
		+ Can lead to unexpected behavior if used incorrectly (e.g., modifying other properties of the same object).
2. **`const { a, ...rest } = obj;`**:
	* Pros:
		+ More efficient and safe than `delete` because it doesn't modify the original object.
		+ Works with most JavaScript engines, including modern ones like V8 11.x.
	* Cons:
		+ Requires JavaScript syntax that might not be supported by older browsers or engines.

**Library and its purpose**

There is no explicit library mentioned in this benchmark definition. However, both approaches use native JavaScript features:

1. **`delete` operator**: This is a built-in operator in JavaScript that removes a property from an object.
2. **Destructuring assignment**: This is a syntax feature introduced in ECMAScript 2015 (ES6) that allows extracting properties from objects into separate variables.

**Special JS feature or syntax**

The destructuring assignment method uses ES6+ syntax, which might not be supported by older JavaScript engines or browsers. However, MeasureThat.net seems to provide results for both Safari 17 (which supports ES6+) and an older browser version, suggesting that the benchmark is designed to accommodate different JavaScript environments.

**Other alternatives**

If you wanted to test other approaches to removing properties from objects in JavaScript, some alternatives could be:

1. **`Object.assign({}, obj)`**: This method creates a new object with the same properties as `obj`, but without the specified property.
2. **`JSON.parse(JSON.stringify(obj))`**: This method creates a new object by cloning the original object's properties, excluding the specified property.
3. **Using a library like Lodash or Underscore.js**: These libraries provide utility functions for working with objects, including removing properties.

Keep in mind that these alternatives might have different performance characteristics and are often used for specific use cases or edge cases.

Related benchmarks:

Delete vs Rest object (version: 0)

Measure the performance of delete a prop versus removing a prop using rest object

Comparing performance of: Delete vs Rest object

Created: 2 years ago by: Guest

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):