Benchmark: spread vs Push Loop

Script Preparation code:

var subarrs = [
 [ "hello", true, 7 ],
 [ "yes", "no", "maybe", false, 27 ],
 [ 16, "I", "wonder", "what", "will", "be", "fastest"]
];

Tests:

1
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ for (var jarr = subarrs[i], jen = jarr.length, j = 0; j < jen; j++){ other.push(jarr[j]); } } return other;
2
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ other.push(...subarrs[i]); } return other;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
1
2

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is a complex task, and the provided benchmark definition is a great example of how to create a microbenchmark.

**What's being tested:**
The benchmark tests two approaches for adding elements to an array:

1. The "Push Loop" approach uses a traditional `for` loop with two nested loops to iterate over each element in the subarray and push it onto the main array.
2. The "Spread Operator" approach uses the spread operator (`...`) to add all elements of a subarray directly into the main array.

**Options being compared:**
The benchmark compares the performance of these two approaches under different conditions, including:

* Different sizes of subarrays (not explicitly shown in the provided data, but presumably tested)
* Potential optimizations, such as reducing unnecessary computations or minimizing memory allocation

**Pros and Cons:**

1. **Push Loop Approach:**
	* Pros:
		+ Can be more intuitive for developers familiar with traditional loops.
		+ Allows for fine-grained control over iteration order and bounds checking.
	* Cons:
		+ Can lead to slower performance due to repeated push operations and unnecessary loop overhead.
		+ May require additional computations or memory allocations, reducing overall efficiency.
2. **Spread Operator Approach:**
	* Pros:
		+ More concise and expressive syntax, making it easier to read and maintain code.
		+ Reduces boilerplate code and eliminates the need for explicit loops.
	* Cons:
		+ May be less intuitive for developers unfamiliar with the spread operator.
		+ Can lead to slower performance if not optimized correctly (e.g., using unnecessary `push` operations).

**Library and purpose:**
In this benchmark, no specific libraries are used beyond the standard JavaScript features. The use of the spread operator is a built-in feature introduced in ECMAScript 2015.

**Special JS feature or syntax:**
The use of the spread operator (`...`) is a notable feature in modern JavaScript. While not directly related to performance, it's worth mentioning that this benchmark highlights the trade-offs between conciseness and performance when using modern features.

**Other alternatives:**
In general, other approaches for adding elements to an array might include:

* Using `Array.prototype.concat()` or `Array.prototype.pushAll()`
* Implementing a custom, optimized loop (e.g., using SIMD instructions)
* Leveraging WebAssembly (WASM) or other low-level performance optimizations

Keep in mind that the specific alternatives would depend on the target use case, platform, and optimization goals.

Overall, this benchmark provides a useful comparison of two approaches to adding elements to an array, highlighting the trade-offs between conciseness, readability, and performance.

Related benchmarks:

spread vs Push Loop (version: 0)

Comparing performance of: 1 vs 2

Created: 3 years ago by: Guest

Jump to the latest result

1

2

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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