Benchmark: concat vs spread vs empty spread vs push (performance)

Tests:

concat
var params = ["hello", true, 7]; var other = params.concat([1]);
spread
var params = ["hello", true, 7] var other = [...params, 1]
empty spread
var other = [...[], 1]
push
var params = ["hello", true, 7]; params.push(1);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat
spread
empty spread
push

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.

**What is being tested on the provided JSON?**

The test cases are designed to compare the performance of four different approaches for concatenating an array:

1. `concat()`: A traditional method for concatenating arrays, which involves creating a new array and adding elements to it.
2. Spread operator (`...`): The new ES6 spread operator allows you to create a new array by spreading the elements of an existing array or object.
3. Empty spread (`[]`): This approach uses the empty spread operator to create a new array, which is then used as a base for concatenation.
4. `push()`: A method for adding elements to the end of an array.

**Options comparison**

The test cases are designed to compare these four approaches:

* **Pros and Cons:**
	+ `concat()`:
		- Pros: Simple, straightforward implementation; works well for small arrays.
		- Cons: Creates a new array, which can be memory-intensive for large arrays.
	+ Spread operator (`...`):
		- Pros: More efficient than `concat()` since it only creates a single new array element; preserves the original array's structure.
		- Cons: May have performance issues with very large arrays due to the spread operator's nature (it uses a heap allocation).
	+ Empty spread (`[]`):
		- Pros: Similar to `push()`, but avoids the overhead of a function call; can be more efficient for small arrays.
		- Cons: May not be suitable for large arrays since it creates an empty array and then adds elements.
	+ `push()`:
		- Pros: Efficient, as it only modifies the existing array without creating a new one.
		- Cons: Can be slower than spread operator or `concat()` due to the overhead of pushing elements onto the end of the array.
* **Other considerations:**
	+ The test cases do not include any other methods for concatenating arrays, such as using `Array.prototype.splice()`, `Array.prototype.unshift()`, or other libraries.
	+ There is no consideration of the order in which elements are added to the array.

**Libraries and special JS features**

* **No notable library usage**: The test cases do not rely on any specific JavaScript libraries.
* **ES6 spread operator**: Introduced in ECMAScript 2015 (ES6), this feature allows you to create a new array by spreading elements from an existing array or object.

**Other alternatives**

If other methods for concatenating arrays were included, some alternative approaches could include:

* Using `Array.prototype.splice()`: This method modifies the original array by removing and adding elements.
* Using `Array.prototype.unshift()`: This method adds one or more elements to the beginning of the array.
* Using a library like Lodash (e.g., `_.concat()`, `_merge`) for concatenation.

Keep in mind that these alternatives might have different performance characteristics, memory usage, or compatibility issues with older browsers.

Related benchmarks:

concat vs spread vs empty spread vs push (performance) (version: 0)

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

Comparing performance of: concat vs spread vs empty spread vs push

Created: 7 years ago by: Guest

Jump to the latest result

concat

spread

empty spread

push

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):