Benchmark: let + delete vs deconstruct

Script Preparation code:

var obj = {
  foo: 1,
  bar: 2,
}

Tests:

delete
var foo = obj.foo; if (obj.foo) delete obj.foo;
deconstruct
const {foo, ...rest} = obj;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
delete
deconstruct

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 break down the provided benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark is defined by two test cases: "delete" and "deconstruct". The script preparation code for both tests is similar, but with different approaches to delete property from an object. Let's analyze each approach:

1. **Delete Approach**: `var foo = obj.foo; if (obj.foo) delete obj.foo;`
	* This approach creates a temporary variable `foo` and assigns the value of `obj.foo`. Then, it checks if `obj.foo` is truthy and deletes it.
	* Pros:
		+ Allows for a simple and readable way to delete properties from an object.
	+ Can be useful in situations where you need to access the deleted property before deleting it.
	* Cons:
		+ Creates a temporary variable, which can lead to increased memory allocation.
		+ May not be as efficient as other approaches, especially for large objects or high-performance applications.
2. **Deconstruct Approach**: `const {foo, ...rest} = obj;`
	* This approach uses destructuring assignment to create two variables: `foo` and `rest`. The `foo` variable is assigned the value of `obj.foo`, while the `rest` variable captures all other properties in the object.
	* Pros:
		+ Eliminates the need for a temporary variable, reducing memory allocation and potential performance gains.
		+ Can be more efficient than the delete approach, especially for large objects or high-performance applications.
	* Cons:
		+ May not be as readable or intuitive for developers unfamiliar with destructuring assignment.
		+ Requires JavaScript support (ES6+) to work.

**Library Usage**

In this benchmark, there is no explicit library usage. However, it's worth noting that some modern browsers, like Chrome, may use internal libraries or optimizations that could potentially affect the results of this benchmark.

**Special JS Features/Syntax**

There are two special JavaScript features used in this benchmark:

1. **Destructuring Assignment**: Used in the "deconstruct" test case to assign properties from an object to separate variables.
2. **ES6+ Syntax**: The destructuring assignment syntax (e.g., `const {foo, ...rest} = obj;`) requires support for ECMAScript 2015 (ES6+) features.

**Other Alternatives**

Alternative approaches to delete properties from an object include:

1. **Object.defineProperty()**: A more low-level approach that allows you to define a property descriptor and then use the `delete` operator.
2. **Object.keys() and Array.prototype.forEach()**: You can iterate over an object's keys using `Object.keys()` and then delete each key individually.

These alternative approaches may have different performance characteristics or require additional code, making them less suitable for certain use cases.

Overall, this benchmark compares the performance of two common approaches to deleting properties from an object: the "delete" approach (using a temporary variable) and the "deconstruct" approach (using destructuring assignment). The results suggest that the deconstruct approach may be more efficient, especially in high-performance applications.

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.75 Safari/537.36

Browser/OS: Chrome 77 on Linux

View result in a separate tab

Test name	Executions per second
delete	6433831.5 Ops/sec
deconstruct	1595830.2 Ops/sec

Related benchmarks:

let + delete vs deconstruct (version: 0)

Comparing performance of: delete vs deconstruct

Created: 5 years ago by: Guest

Jump to the latest result

delete

deconstruct

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):