Benchmark: Array.prototype.concat new vs spread operator

Tests:

Array.prototype.concat
var defaultSkippedFields = ['correlationId']; var additionalSkippedFields = ['test123']; var skippedFields = (new Array()).concat(defaultSkippedFields).concat(additionalSkippedFields);
spread operator
var defaultSkippedFields = ['correlationId']; var additionalSkippedFields = ['test123']; var skippedFields = [...defaultSkippedFields, ...additionalSkippedFields];

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:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark compares two approaches for concatenating arrays in JavaScript:

1. **Traditional `concat()` method**: This is the older way of concatenating arrays using the `+` operator or the `concat()` function.
2. **New ES6 spread operator (`...`)**: Introduced in ECMAScript 2015, this operator allows you to create a new array by spreading elements from existing arrays.

**Test Cases**

There are two test cases:

1. **Array.prototype.concat**: This test case uses the traditional `concat()` method to concatenate an array with another array.
2. **Spread Operator**: This test case uses the new ES6 spread operator (`...`) to create a new array by spreading elements from existing arrays.

**Pros and Cons**

**Traditional `concat()` Method:**

Pros:

* Widely supported and well-established in JavaScript history
* Easy to understand and use, especially for developers familiar with older JavaScript versions

Cons:

* Can be slower than the spread operator due to its overhead
* Creates a new array object every time it's used, which can lead to performance issues for large datasets

**New ES6 Spread Operator (`...`):**

Pros:

* Faster execution speed compared to the traditional `concat()` method
* More memory-efficient since it doesn't create a new array object every time
* Simplifies code and improves readability

Cons:

* Requires JavaScript 2015 or later support
* May have issues with older browsers or environments that don't understand the spread operator

**Library: None**

There is no explicit library mentioned in the benchmark. The `Array.prototype.concat` method is a built-in JavaScript function, while the new ES6 spread operator (`...`) is also part of the standard JavaScript syntax.

**Special JS Feature/Syntax: Spread Operator (if not already mentioned)**

The spread operator is a new feature introduced in ECMAScript 2015. It allows you to create a new array by spreading elements from existing arrays or objects. For example:
```javascript
const arr = [1, 2, 3];
const newArr = [...arr]; // creates a new array [1, 2, 3]
```
This syntax was added to the JavaScript language standard in ECMAScript 2015, which is why it's only supported in modern browsers and environments.

**Alternatives**

Other alternatives for concatenating arrays include:

* Using the `Array.prototype.push()` method with an array of elements as its argument (e.g., `arr.push(...newArr)`).
* Using a library like Lodash, which provides a `concat` function that may be faster or more efficient than the built-in `concat()` method.
* Using a different data structure, such as a linked list or a dynamic array, to concatenate elements.

However, for most use cases, the traditional `concat()` method and the new ES6 spread operator (`...`) will suffice. The benchmark provides an objective comparison of these two approaches, allowing developers to make informed decisions about which one to use in their code.

Related benchmarks:

Array.prototype.concat new 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: 4 years ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

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):