Benchmark: [test] Concat vs spread

Tests:

concat
const first = [1, 2, 3, 4, 5, 6] const second = [1, 2, 3, 4, 5, 6] const third = first.concat(second);
spread
const first = [1, 2, 3, 4, 5, 6] const second = [1, 2, 3, 4, 5, 6] const third = [ ...first, ...second ];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat
spread

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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**Overview**

The provided benchmark measures the performance difference between two approaches: concatenating arrays using the `concat()` method and using the spread operator (`...`) to create a new array from existing ones.

**Test Cases**

There are two test cases:

1. **Concat**: This test case creates two identical arrays, `first` and `second`, with 6 elements each. It then calls the `concat()` method on these two arrays to concatenate them into a single array, `third`.
2. **Spread**: This test case also creates two identical arrays, `first` and `second`, with 6 elements each. However, instead of using the `concat()` method, it uses the spread operator (`...`) to create a new array, `third`, by spreading the elements of both `first` and `second` into it.

**Library/Functions Used**

None in this benchmark. The tests only use built-in JavaScript functions and arrays.

**Special JS Features/Syntax**

The benchmark uses two advanced features:

1. **Spread Operator (`...`)**: Introduced in ECMAScript 2015, the spread operator allows you to create a new array by spreading the elements of an existing array or object into a new one.
2. **Template Literals (`\r\n`)**: Used to write multi-line strings in JavaScript.

**Options Compared**

The benchmark compares two approaches:

1. **Concat**: The traditional way of concatenating arrays using the `concat()` method.
2. **Spread**: A more modern approach using the spread operator to create a new array from existing ones.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

**Concat (Traditional Method)**

Pros:

* Wide compatibility across older browsers
* Simple to implement
* Fast performance in some cases

Cons:

* Less efficient than the spread operator for large arrays
* May not be optimized by modern JavaScript engines

**Spread (Modern Approach)**

Pros:

* More efficient than `concat()` for large arrays
* Safer and more predictable, as it avoids modifying the original array
* Wide adoption in modern JavaScript codebases

Cons:

* May require browser support for ECMAScript 2015 features
* Less readable for some developers, especially those familiar with older approaches

**Considerations**

When choosing between `concat()` and the spread operator, consider the following factors:

* **Array size**: For large arrays, the spread operator is generally more efficient.
* **Browser compatibility**: If you need to support older browsers, use the traditional `concat()` method.
* **Readability and maintainability**: Choose the approach that best fits your codebase's style and conventions.

**Other Alternatives**

If you're interested in exploring alternative approaches, consider:

1. **Array.prototype.push()**: A more efficient way of concatenating arrays by adding elements to the end of an existing array.
2. **Array.prototype.set()**: An even more modern approach, which allows creating a new array with a specific length and filling it with values.

Keep in mind that these alternatives may not be supported by older browsers or require additional dependencies.

Related benchmarks:

[test] Concat vs spread (version: 0)

Comparing performance of: concat vs spread

Created: 5 years ago by: Guest

Jump to the latest result

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):