Benchmark: Array.prototype.concat vs spread operator test

Tests:

Array.prototype.concat
var params = [ "hello", true, 7 ]; var other = [ 1, 2 ].concat(params);
spread operator
var params = [ "hello", true, 7 ] var other = [ 1, 2, ...params ]

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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 the explanation of the provided benchmark.

The test being measured is the performance comparison between two approaches for concatenating arrays in JavaScript: the traditional `concat()` method and the new ES6 spread operator (`...`).

**Options Compared**

Two options are compared:

1. **Array.prototype.concat**: This method creates a new array by copying elements from one or more source arrays.
2. **Spread Operator (new ES6 syntax)**: The `...` operator is used to expand an array into separate arguments.

**Pros and Cons of Each Approach**

* **Array.prototype.concat**:
	+ Pros:
		- Well-established and widely supported method.
		- Can be more readable for some developers.
	+ Cons:
		- Creates a new array, which can lead to increased memory usage.
		- May have performance overhead due to the overhead of creating a new array object.
* **Spread Operator (new ES6 syntax)**:
	+ Pros:
		- More concise and expressive than `concat()`.
		- Reduces memory allocation and copying since it doesn't create a new array.
	+ Cons:
		- Less readable for some developers due to its unconventional syntax.
		- May have performance overhead due to the creation of intermediate arrays.

**Library Used**

None, as this benchmark only uses built-in JavaScript features.

**Special JS Features or Syntax**

The spread operator (`...`) is a new feature introduced in ECMAScript 2015 (ES6). It allows for more concise array manipulation and expansion.

**Other Alternatives**

In addition to `concat()` and the spread operator, there are other ways to concatenate arrays in JavaScript:

* **Array.prototype.push()**: You can push elements from an existing array onto a new array using `push()`. However, this approach is generally slower than `concat()` due to the overhead of modifying an existing array.
* **Array.prototype.slice() + Array.prototype.concat()**: Another common approach is to use `slice()` to create a shallow copy of one array and then concatenate it with another array. While more flexible than just using `concat()`, this approach can be slower due to the intermediate array creation.

Keep in mind that these alternatives may not be as well-supported or optimized as the original `concat()` method or spread operator.

In summary, the benchmark tests the performance of two commonly used methods for concatenating arrays: `Array.prototype.concat` and the spread operator. The results will help developers understand the trade-offs between readability, memory usage, and performance when choosing these approaches in their JavaScript code.

Related benchmarks:

Array.prototype.concat vs spread operator test (version: 0)

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

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

Created: 7 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):