Benchmark: ES6 Array concat vs spread operator

Script Preparation code:

var original = [ 1, 2 ];
var params = [ "hello", true, 7 ];

Tests:

Array.prototype.concat
return original.concat(params);
spread operator
return [...original, ...params ]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Linux; Android 7.1.1; MI 6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Mobile Safari/537.36

Browser/OS: Chrome Mobile 70 on Android 7.1.1

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	1158696.2 Ops/sec
spread operator	1742741.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks and analyze the provided test cases.

**Benchmark Definition**

The benchmark is designed to compare two approaches for concatenating arrays in JavaScript: the traditional `Array.prototype.concat()` method and the new ES6 spread operator (`[...array, ...elements]`).

**Options Compared**

Two options are being compared:

1. **Traditional Concat Method**: `original.concat(params)`
	* This approach uses the `concat()` method to concatenate two arrays.
	* The original array is modified in-place, which can be a performance bottleneck if not needed.
2. **Spread Operator**: `[...original, ...params]`
	* This approach uses the spread operator (`[...]`) to create a new array by copying elements from the original array and then spreading the parameters array.

**Pros and Cons of Each Approach**

**Traditional Concat Method**

Pros:

* Easy to understand and implement
* Wide support across browsers and JavaScript engines

Cons:

* Modifies the original array, which can lead to unexpected behavior if not intended
* May have performance implications due to in-place modification

**Spread Operator**

Pros:

* Creates a new array, avoiding potential issues with modifying the original array
* Can be more efficient than traditional concatenation methods

Cons:

* Requires support for the spread operator (introduced in ES6)
* Can lead to higher memory allocation if not used carefully

**Other Considerations**

Both approaches have implications on memory usage and performance. The spread operator can create a new array, which may lead to increased memory allocation. However, this is often considered beneficial when avoiding side effects of modifying the original array.

**Library or Special JS Feature**

None of the provided test cases use any external libraries or special JavaScript features beyond the ES6 spread operator. The focus is on comparing the two approaches for array concatenation.

**Test Case Interpretation**

The test case uses a simple example with an array `original` and parameters `params`. The benchmark measures the execution time of each approach, allowing users to compare their performance.

**Alternative Approaches**

Other approaches for array concatenation include:

1. Using the `Array.prototype.push()` method: `original.push(...params)`
2. Using the `Array.prototype.reduce()` method: `original.reduce((acc, elem) => acc.concat(elem))`
3. Using a loop to concatenate elements: `for (let i = 0; i < params.length; i++) { original[i] = params[i]; }`

These alternatives may offer different trade-offs in terms of performance, memory usage, and code readability.

In summary, the provided benchmark compares two approaches for array concatenation in JavaScript: traditional `Array.prototype.concat()` method and the new ES6 spread operator. The test case focuses on measuring execution time to help users determine which approach is faster and more suitable for their use cases.

Related benchmarks:

ES6 Array concat vs spread operator (version: 0)

Compare the new ES6 spread operator with the traditional concat() method

Comparing performance of: Array.prototype.concat vs spread operator

Created: 6 years ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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