Benchmark: spread vs concat vs unshift (v96)

Script Preparation code:

var array = [1,2,3];

Tests:

arrayUnshift123
array.unshift(0);
arrayConcat123
array = [0].concat(array)
arraySpread123
array = [0, ...array]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
arrayUnshift123
arrayConcat123
arraySpread123

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, compared, and some pros and cons of each approach.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmarking test case on the MeasureThat.net website. The test case compares three different ways to manipulate an array in JavaScript:

1. `unshift`: adding an element to the beginning of an array.
2. `concat`: concatenating two arrays using the `+` operator or the `concat()` method.
3. `unshift (spread syntax)`: using the spread operator (`...`) to add elements to the beginning of an array.

**Script Preparation Code**

The script preparation code is provided as:
```javascript
var array = [1, 2, 3];
```
This creates a simple array with three elements and assigns it to the variable `array`.

**Html Preparation Code**

There is no HTML preparation code provided, so we can assume that this test case only tests the JavaScript engine's performance.

**Individual Test Cases**

The individual test cases are:

1. `arrayUnshift123`: testing the `unshift()` method.
2. `arrayConcat123`: testing the `concat()` method using both the `+` operator and the `concat()` method.
3. `arraySpread123`: testing the spread syntax (`...`) to add elements to the beginning of an array.

**Library Usage**

There is no explicit library usage in this benchmark, but it's worth noting that JavaScript arrays are a built-in data structure in most modern browsers.

**Special JS Features/Syntax**

The test case uses the spread operator (`...`), which was introduced in ECMAScript 2015 (ES6). This allows for concise array creation and manipulation.

Here are some pros and cons of each approach:

1. `unshift()`:
	* Pros: Simple, efficient way to add elements to an array.
	* Cons: Can be slower than other methods due to the overhead of modifying an existing array.
2. `concat()`:
	* Pros: Can be faster than `unshift()`, especially for large arrays, since it creates a new array and assigns it to a variable.
	* Cons: Can lead to memory leaks if not used carefully, as it creates a new object on the heap.
3. Spread syntax (`...`):
	* Pros: Concise way to create an array by adding elements, making it easier to read and write.
	* Cons: May be slower than other methods due to the overhead of creating a new array.

**Other Alternatives**

If you wanted to test these approaches using a different method, some alternatives could include:

1. Using `push()` instead of `unshift()`.
2. Using `slice()` instead of `concat()`.
3. Testing the performance of custom array implementations.
4. Comparing the performance of different JavaScript engines (e.g., V8, SpiderMonkey).

Keep in mind that these alternative test cases might require significant changes to the benchmark code and may not provide comparable results.

Overall, this benchmark provides a useful comparison of three common ways to manipulate arrays in JavaScript, allowing users to evaluate their own coding choices and optimize performance-critical sections of code.

Related benchmarks:

spread vs concat vs unshift (v96) (version: 0)

spread vs concat vs unshift

Comparing performance of: arrayUnshift123 vs arrayConcat123 vs arraySpread123

Created: 5 years ago by: Guest

Jump to the latest result

arrayUnshift123

arrayConcat123

arraySpread123

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):