Benchmark: Array concat vs spread test

Tests:

Array.prototype.concat
const first = [ 1, 2, 3 ] const second = [ 4, 5, 6 ] return first.concat(second);
spread operator
var first = [ 1, 2, 3 ] var second = [ 4, 5, 6 ] return [...first, ...second];

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Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator

Fastest: N/A

Slowest: N/A

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

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Let's dive into explaining the JavaScript microbenchmark.

The test is designed to compare two approaches for concatenating arrays in JavaScript: the traditional `concat()` method and the new ES6 spread operator (`...`).

**Traditional Approach (Array.prototype.concat)**

This approach uses the `concat()` method, which is a built-in array method that returns a new array with all elements from the original array and the additional array.

Here's an excerpt of the benchmark definition:
```javascript
return first.concat(second);
```
The pros of this approach are:

1. **Wide browser support**: The `concat()` method has been part of the JavaScript language since its inception and is supported by most browsers.
2. **Simple to implement**: No special syntax or features are required.

However, there are some cons:

1. **Slow performance**: The `concat()` method creates a new array and copies all elements from both arrays, which can be inefficient for large datasets.
2. **Creates unnecessary intermediate objects**: When the resulting array is modified later, an additional object is created to store the modified values.

**New ES6 Spread Operator (Spread Syntax)**

This approach uses the spread syntax (`...`) introduced in ES6 to create a new array with all elements from both arrays.

Here's an excerpt of the benchmark definition:
```javascript
return [...first, ...second];
```
The pros of this approach are:

1. **Fast performance**: The spread operator creates a new array without copying elements from both arrays, resulting in faster execution times.
2. **Efficient memory usage**: Only one intermediate object is created when the resulting array is modified later.

However, there are some cons:

1. **Browser support limitations**: Not all browsers support the ES6 spread operator, although it's widely supported by modern browsers like Chrome and Firefox.
2. **Unfamiliar syntax for some developers**: The spread operator may be unfamiliar to developers who haven't used it before.

**Other Considerations**

When choosing between these two approaches, consider the trade-off between performance and browser support. If you need to run your code in older browsers or require faster execution times, the spread operator might be a better choice.

**Additional Library Usage**

In this benchmark, there is no explicit library usage mentioned. However, it's worth noting that some benchmarks may use libraries like Benchmark.js or Microbenchmark to measure performance.

**Special JS Feature or Syntax**

This benchmark uses a feature introduced in ES6: the spread operator (`...`). This syntax allows you to create new arrays by spreading elements from existing arrays.

The `ExecutionsPerSecond` values indicate the number of executions performed per second, which is an important metric for measuring performance. In this case, the spread operator performs significantly better than the traditional `concat()` method.

Related benchmarks:

Array concat vs spread test (version: 0)

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

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

Created: 2 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):