Benchmark: push vs spread in while loop

Script Preparation code:

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

Tests:

while spread
var other = [ 1, 2, 3 ] var l = subarrs.length while(l--) { other = [ ...other, ...subarrs[l] ] } return other;
while push
var other = [ 1, 2, 3 ] var l = subarrs.length while(l--) { let ls = subarrs[l].length while(ls--) { other.push(subarrs[l][ls]) } } return other;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
while spread
while push

Fastest: N/A

Slowest: N/A

Latest run results:

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

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

**Benchmark Overview**

The test compares two approaches to adding elements from an array `subarrs` to another array `other` in a while loop. The arrays contain different types of data, including strings, booleans, numbers, and nested arrays.

**Approaches Compared**

There are two benchmarked approaches:

1. **While Push**: This approach uses the `push()` method to add elements from `subarrs` to `other`. The loop iterates over `subarrs` using an index variable `l`, which decrements on each iteration.
2. **While Spread**: This approach uses the spread operator (`...`) to concatenate arrays, similar to the `push()` method. However, instead of using `push()`, it creates a new array with each element from `subarrs` added to `other`.

**Pros and Cons of Each Approach**

**While Push**

Pros:

* Efficient use of memory, as only one array is created.
* Can be faster for large arrays.

Cons:

* May require more iterations to add all elements, depending on the array length.
* If the `push()` method is optimized, it may not provide a significant performance advantage.

**While Spread**

Pros:

* Creates a new array with each element added, which can be more predictable and efficient.
* Does not modify the original arrays, which can reduce side effects.

Cons:

* May require more memory allocation due to the creation of temporary arrays.
* Can be slower for very large arrays.

**Library and Special JS Features**

There is no library used in this benchmark. However, it does utilize a special JavaScript feature: the spread operator (`...`). The `...` operator was introduced in ECMAScript 2015 (ES6) and allows for creating new arrays by spreading elements from existing arrays.

**Other Alternatives**

If these two approaches are not sufficient, other alternatives could include:

* Using `Array.prototype.concat()` to concatenate arrays.
* Using `Array.prototype.forEach()` to iterate over the elements of an array.
* Optimizing the loop using techniques like caching or memoization.

It's worth noting that the choice of approach depends on the specific requirements and constraints of the application, such as performance, memory usage, and code readability.

Related benchmarks:

push vs spread in while loop (version: 0)

Comparing performance of: while spread vs while push

Created: 4 years ago by: Guest

Jump to the latest result

while spread

while push

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):