Benchmark: JS Concat vs Spread - 1arr

Script Preparation code:

var sampleArr = new Array(50000).fill('a')

Tests:

Concat
var result = sampleArr.concat(['b','c'])
Spread
var result = [...sampleArr, 'b','c']

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Concat
Spread

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 dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**What is tested:**
The benchmark tests the performance difference between two approaches to concatenate an array in JavaScript:

1. `concat()`: The traditional method of concatenating arrays using the `concat()` method.
2. Spread syntax (`...`): A newer, more concise way to concatenate arrays using the spread operator.

**Options compared:**

* **Concat**: Uses the `concat()` method to concatenate two arrays.
	+ Pros:
		- Widely supported and well-known in JavaScript.
		- Often used in codebases due to its simplicity.
	+ Cons:
		- Can be slower than the spread syntax for large arrays due to the overhead of function calls.
* **Spread**: Uses the spread operator (`...`) to concatenate two arrays.
	+ Pros:
		- Faster and more concise than `concat()` for large arrays.
		- Modern JavaScript syntax that's gaining popularity.
	+ Cons:
		- Not supported in older browsers or environments (e.g., Internet Explorer).
		- May not be as familiar to some developers.

**Other considerations:**

* **Array.prototype.push()**: An alternative approach would be using `push()` method on the first array and passing the second array as an argument. However, this approach is less common due to its slightly different behavior (it modifies the original array instead of creating a new one).
* **String concatenation**: Another approach would be using string concatenation (`'a'.concat('b')` or `'a' + 'b'`) for small arrays, as it's often faster than the array concatenation methods. However, this approach is not applicable here since we're dealing with large arrays.

**Library and special JS feature:**
There are no specific libraries mentioned in the benchmark definition. The spread syntax (`...`) is a built-in JavaScript feature introduced in ECMAScript 2015 (ES6).

**Other alternatives (not tested):**

* `Array.prototype.splice()`: An alternative approach would be using `splice()` method on the first array and passing the second array as an argument. However, this approach is less common due to its slightly different behavior (it modifies the original array instead of creating a new one).
* `Array.prototype.push.apply()`: Another alternative would be using `push.apply()` method on the first array, which is similar to `concat()`. However, it's not as widely used or well-known.

In summary, MeasureThat.net benchmarks the performance difference between traditional `concat()` and modern spread syntax for concatenating arrays in JavaScript. While both approaches have their pros and cons, the spread syntax is generally faster and more concise, making it a popular choice among developers.

Related benchmarks:

JS Concat vs Spread - 1arr (version: 0)

Comparing performance of: Concat vs Spread

Created: 4 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):