Benchmark: Memory Usage 2 - MeasureThat.net

Script Preparation code:

window.count = 1000000000;
window.x = { }
for (let i = 0; i < window.count; i++) { x[i] = i; }

Tests:

undefined
for (let i = 0; i < window.count; i++) { x[i] = undefined; }
delete
for (let i = 0; i < window.count; i++) { delete x[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
undefined
delete

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

I'd be happy to help you understand the JavaScript microbenchmarking test case provided by MeasureThat.net.

**Benchmark Definition**

The benchmark measures the performance of two approaches: creating and deleting objects in an array using the `undefined` and `delete` keywords, respectively. The script preparation code initializes a large array `x` with 1 million elements and assigns each element a unique value.

**Options Compared**

There are two options being compared:

1. **Create and delete objects using `undefined`**: This approach creates an object in the `x[i]` position of the array, sets its value to `undefined`, and then deletes it.
2. **Delete objects directly from the array**: This approach uses the `delete` keyword to remove the objects from the `x[i]` positions of the array without assigning a new value.

**Pros and Cons**

1. **Create and delete objects using `undefined`**:
	* Pros: This approach allows for a more traditional JavaScript object creation and deletion pattern, which might be closer to real-world usage scenarios.
	* Cons: It may lead to unnecessary memory allocations and deallocations due to the `undefined` assignment step.
2. **Delete objects directly from the array**:
	* Pros: This approach avoids the unnecessary `undefined` assignment step and can potentially reduce memory allocations and deallocations.
	* Cons: It may not accurately represent real-world usage scenarios, as it doesn't simulate object creation and destruction in the same way.

**Other Considerations**

The benchmark also considers the impact of JavaScript's garbage collection mechanism on performance. The `window.count` variable is set to a large value to induce significant memory allocations and deallocations, which can affect the results.

**Library and Special JS Features**

There are no libraries used in this benchmark, as it only relies on basic JavaScript features.

**Special JS Features**

The benchmark uses two special JavaScript features:

1. **Let/const declaration**: The `let` and `const` keywords are used to declare variables, which is a relatively new feature introduced in ECMAScript 2015 (ES6).
2. **Template literals**: There are no template literals used in this benchmark.

**Alternative Approaches**

There are alternative approaches that could be used to measure performance in similar scenarios:

1. **Object Pooling**: Instead of creating and deleting objects directly, an object pool approach can be used, where a fixed number of objects is allocated upfront and reused throughout the execution.
2. **Native Array Operations**: Some browsers provide native array operations that can be used for performance-critical code paths, such as SIMD (Single Instruction, Multiple Data) instructions.

In summary, this benchmark measures the performance of two approaches to creating and deleting objects in an array using JavaScript's `undefined` and `delete` keywords. The results can help identify which approach is more efficient in practice, taking into account the impact of JavaScript's garbage collection mechanism.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36

Browser/OS: Chrome 79 on Windows

View result in a separate tab

Test name	Executions per second
undefined	276.9 Ops/sec
delete	388.5 Ops/sec

Related benchmarks:

Memory Usage 2 (version: 1)

Comparing performance of: undefined vs delete

Created: 4 years ago by: Registered User

Jump to the latest result

undefined

delete

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):