Benchmark: Spread vs Push to Same Array

Tests:

Spread
const arr1 = ['a', 'b', 'c'] arr1 = [...arr1,'d']
Push
const arr1 = ['a', 'b', 'c'] arr1.push('d')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread
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 provided JSON benchmark data and explain what is tested, compared, and the pros/cons of different approaches.

**Benchmark Overview**

The benchmark measures the performance difference between two ways to add an element to an array: using the spread operator (`[...arr1,'d']`) and pushing a new element onto the end of the array (`arr1.push('d')`). The goal is to determine which approach is faster for small arrays.

**Benchmark Definition**

The benchmark definition JSON specifies that there is no specific code snippet to be executed, but instead, two pre-defined test cases are provided:

* "Spread": This test case uses the spread operator to create a new array and add an element to it. The code snippet: `const arr1 = ['a', 'b', 'c']\r\narr1 = [...arr1,'d']`
* "Push": This test case uses the push method to add an element to the end of the existing array. The code snippet: `const arr1 = ['a', 'b', 'c']\r\narr1.push('d')`

**Comparison**

In both test cases, the same initial array (`const arr1 = ['a', 'b', 'c']`) is created and then modified by adding a new element.

**Pros/Cons of Different Approaches**

* **Spread Operator (Array Destructuring)**:
	+ Pros:
		- Creates a new array with the original elements and the added one.
		- Does not modify the original array.
		- Can be more efficient for large arrays since it avoids using `push` method, which can lead to reallocation of memory.
	+ Cons:
		- May be slower than push method due to the creation of a new array object.
* **Push Method**:
	+ Pros:
		- Fast and efficient for adding elements to an existing array.
		- Does not create a new array, which can reduce memory allocation.
	+ Cons:
		- Modifies the original array.
		- Can lead to reallocation of memory if the array grows significantly.

**Library/Functions Used**

None are explicitly mentioned in this benchmark. However, the `push` method is a built-in JavaScript function used by both test cases.

**Special JS Features/Syntax**

The benchmark does not use any special JavaScript features or syntax that requires specific explanation. It only uses basic JavaScript data structures and methods.

**Other Alternatives**

For measuring performance differences between array operations, you might also consider using other benchmarking frameworks or libraries, such as:

* jsbench: A popular online JavaScript testing framework that allows you to write and run benchmarks.
* Benchmark.js: A lightweight JavaScript benchmarking library that provides a simple way to measure the execution time of code snippets.

Keep in mind that different benchmarking tools might have varying results due to factors like environment, browser, and hardware.

Related benchmarks:

Spread vs Push to Same Array (version: 0)

Comparing performance of: Spread vs Push

Created: 5 years ago by: Guest

Jump to the latest result

Spread

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):