Benchmark: spread vs concat vs unshift on 100000

Script Preparation code:

var array = new Array(100000).fill(1);

Tests:

Unshift
array.unshift(0);
Concat
array = [0].concat(array)
Spread
array = [0, ...array]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Unshift
Concat
Spread

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 benchmark and explain what's being tested, compared options, pros and cons, and other considerations.

**Benchmark Definition**

The first JSON object defines a benchmark called "spread vs concat vs unshift on 100000" with three test cases:

1. `array.unshift(0);`
2. `array = [0].concat(array)`
3. `array = [0, ...array]`

This benchmark tests the performance of three different methods to append an element at the beginning of an array: `unshift`, `concat`, and spread operator (`...`).

**Options Compared**

The options being compared are:

1. `unshift`: adds an element to the end of the array
2. `concat`: creates a new array by concatenating two arrays
3. Spread operator (`...`): creates a new array with elements copied from the original array

**Pros and Cons**

Here's a brief summary of each option:

1. **unshift**: This method is efficient because it only needs to update the internal buffer of the array, which requires less memory allocation and copying compared to creating a new array.
	* Pros: Fast and efficient
	* Cons: Can be slower than other methods due to its inherent complexity (i.e., inserting an element at the beginning requires shifting all subsequent elements)
2. **concat**: This method creates a new array by concatenating two arrays, which involves memory allocation and copying data.
	* Pros: Easy to understand and implement
	* Cons: Inefficient for large datasets due to the overhead of creating a new array
3. **Spread operator (`...`)**: This method is similar to `concat`, but creates a new array with elements copied from the original array using a spread operation, which can be faster than `concat`.
	* Pros: Fast and efficient, easy to understand and implement
	* Cons: May not work as expected in older browsers or environments that don't support the spread operator

**Library Usage**

None of these methods rely on any libraries.

**Special JavaScript Features/Syntax**

The use of the spread operator (`...`) is a special feature introduced in ECMAScript 2015 (ES6). It allows creating new arrays by copying elements from an existing array.

**Other Considerations**

When choosing between `unshift`, `concat`, and spread operators, consider the following factors:

* Performance: If you need to append elements frequently, `unshift` is likely the fastest option. For concatenation or spreading data, the spread operator might be faster than `concat`.
* Code readability and maintainability: The spread operator can make code more readable and concise, especially when working with large datasets.
* Browser compatibility: Older browsers may not support the spread operator or have limited support for it.

**Alternatives**

Other methods to append elements at the beginning of an array include:

1. `push` followed by `splice(0, 1, ...array)`: Pushes the element and then uses `splice` to insert it at the beginning.
2. Creating a new array using `Array.prototype.slice.call(array, 0, ...)` or `Array.from()` followed by spread operation.

However, these alternatives might be less efficient than the options being compared in this benchmark.

Related benchmarks:

spread vs concat vs unshift on 100000 (version: 0)

spread vs concat vs unshift

Comparing performance of: Unshift vs Concat vs Spread

Created: 3 years ago by: Guest

Jump to the latest result

Unshift

Concat

Spread

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):