Benchmark: Array splice vs object assignsad

Script Preparation code:

var input = [],
    input2 = {};
for (var i = 0; i < 50000; i++) {
    input.push({
        id: i,
        data: 'something'
    })
    input2[i] = input.push({
        id: i,
        data: 'something'
    });
}

Tests:

Array delete
input.splice(0, 50);
ES6 Object Spread
delete input2[1]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array delete
ES6 Object Spread

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:108.0) Gecko/20100101 Firefox/108.0

Browser/OS: Firefox 108 on Windows

View result in a separate tab

Test name	Executions per second
Array delete	18417874.0 Ops/sec
ES6 Object Spread	22575526.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark and its results in detail.

**What is tested?**

The provided JSON represents a JavaScript microbenchmark that compares two approaches:

1. **Array Splice**: This approach modifies an array by removing or inserting elements at a specific position.
2. **Object Assigns**: This approach creates a new object and assigns values to it, creating a similar structure as the original input.

**Options compared**

The benchmark compares the performance of these two approaches on different platforms (Firefox 108 on Windows Desktop).

**Pros and Cons of each approach:**

1. **Array Splice**:
	* Pros:
		+ Can be used for inserting or removing elements from an array.
		+ Can be more efficient when working with large arrays, as it only requires a single memory allocation.
	* Cons:
		+ Can lead to unexpected behavior if not used carefully, as it modifies the original array.
		+ May not be suitable for use cases where the original array needs to remain intact.
2. **Object Assigns**:
	* Pros:
		+ Creates a new object and assigns values to it, avoiding any potential side effects on the original input.
		+ Can be more predictable and easier to reason about, as it creates a clear separation between the original data and the modified data.
	* Cons:
		+ May require more memory allocations than Array Splice, which can impact performance for large inputs.
		+ Can lead to slower performance due to the overhead of creating a new object.

**Other considerations:**

1. **ES6 Object Spread**: The benchmark uses ES6's object spread syntax (e.g., `delete input2[1]`) to create a shallow copy of the original object, which can be useful in certain scenarios.
2. **Firefox 108**: The benchmark is run on Firefox 108, which may have specific optimizations or quirks that affect performance.

**Other alternatives:**

For creating deep copies of objects, you can consider using libraries like:

1. Lodash (specifically, `_.cloneDeep()`)
2. Underscore.js (`_pickBy()` or `_extend()` with `deep: true`)

Alternatively, you can use the `JSON.parse(JSON.stringify())` trick to create a deep copy of an object.

For inserting or removing elements from arrays, you may want to consider using other libraries like:

1. Ramda (specifically, `R.insert()`, `R.remove()`)
2. Immutable.js (`fromJS()` and `setIn()`)

Keep in mind that the choice of library or approach depends on your specific use case and performance requirements.

Related benchmarks:

Array splice vs object assignsad (version: 0)

Comparing performance of: Array delete vs ES6 Object Spread

Created: 2 years ago by: Guest

Jump to the latest result

Array delete

ES6 Object Spread

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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